Introducing the Adafruit Bluefruit LE UART
Friend
Created by Kevin Townsend
https://learn.adafruit.com/introducing-the-adafruit-bluefruit-le-uart-friend
Last updated on 2022-09-05 08:53:19 PM EDT
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Table of Contents
Introduction
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So it's a Fancy Pants Wireless UART Adapter?
Download our free Android/iOS app and you're ready to rock!
You can do a lot more too!
Why Use Adafruit's Module?
Technical Specifications
Pinouts
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7
10
Power Pins
UART Pins
Other Pins
Reverse Side Breakouts
Assembly
13
• Prepare the header strip:
• Add the breakout board:
• And Solder!
Wiring
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Wiring for Arduino Uno
Wiring for an Arduino MEGA
Not Connecting? Try a Power Cycle
Wiring for an FTDI Cable
Factory Reset
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15
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Factory Reset via DFU Pin
FactoryReset Sample Sketch
AT+FACTORYRESET
Factory Reset via FCTR Test Pad
DFU Updates
22
• Adafruit Bluefruit LE Connect
Current Measurements
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23
Test Conditions
Fast Advertising Mode
Slow Advertising Mode
Connected Mode (UART)
Software
25
Configuration!
26
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Which board do you have?
Bluefruit Micro or Feather 32u4 Bluefruit
Feather M0 Bluefruit LE
Bluefruit LE SPI Friend
Bluefruit LE UART Friend or Flora BLE
Configure the Pins Used
Common settings:
Software UART
Hardware UART
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Mode Pin
SPI Pins
Software SPI Pins
Select the Serial Bus
UART Based Boards (Bluefruit LE UART Friend & Flora BLE)
SPI Based Boards (Bluefruit LE SPI Friend)
ATCommand
32
• Opening the Sketch
• Configuration
• Running the Sketch
BLEUart
36
• Opening the Sketch
• Configuration
• Running the Sketch
HIDKeyboard
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Opening the Sketch
Configuration
Running the Sketch
Bonding the HID Keyboard
Android
iOS
OS X
Controller
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49
Opening the Sketch
Configuration
Running the Sketch
Using Bluefruit LE Connect in Controller Mode
Streaming Sensor Data
Control Pad Module
Color Picker Module
HeartRateMonitor
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41
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Opening the Sketch
Configuration
If Using Hardware or Software UART
Running the Sketch
nRF Toolbox HRM Example
CoreBluetooth HRM Example
UriBeacon
61
• Opening the Sketch
• Configuration
• Running the Sketch
HALP!
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Data Mode
65
• Switching Command/Data Mode via +++
Command Mode
68
• Hayes/AT Commands
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Test Command Mode '=?'
Write Command Mode '=xxx'
Execute Mode
Read Command Mode '?'
Dynamically Switching Modes via +++
Standard AT
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AT
ATI
ATZ
ATE
+++
General Purpose
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91
AT+BLEPOWERLEVEL
AT+BLEGETADDRTYPE
AT+BLEGETADDR
AT+BLEGETPEERADDR
AT+BLEGETRSSI
BLE Services
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84
AT+BLEBEACON
AT+BLEURIBEACON
Deprecated: AT+EDDYSTONEENABLE
AT+EDDYSTONEURL
AT+EDDYSTONECONFIGEN
AT+EDDYSTONESERVICEEN
AT+EDDYSTONEBROADCAST
BLE Generic
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78
AT+BAUDRATE
AT+HWADC
AT+HWGETDIETEMP
AT+HWGPIO
AT+HWGPIOMODE
AT+HWI2CSCAN
AT+HWVBAT
AT+HWRANDOM
AT+HWMODELED
AT+UARTFLOW
Beacon
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74
AT+FACTORYRESET
AT+DFU
AT+HELP
AT+NVMWRITE
AT+NVMREAD
AT+MODESWITCHEN
Hardware
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AT+BLEUARTTX
AT+BLEUARTTXF
AT+BLEUARTRX
AT+BLEUARTFIFO
AT+BLEKEYBOARDEN
AT+BLEKEYBOARD
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AT+BLEKEYBOARDCODE
Modifier Values
HID Keyboard Codes
AT+BLEHIDEN
AT+BLEHIDMOUSEMOVE
AT+BLEHIDMOUSEBUTTON
AT+BLEHIDCONTROLKEY
AT+BLEHIDGAMEPADEN
AT+BLEHIDGAMEPAD
AT+BLEMIDIEN
AT+BLEMIDIRX
AT+BLEMIDITX
AT+BLEBATTEN
AT+BLEBATTVAL
BLE GAP
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AT+GAPCONNECTABLE
AT+GAPGETCONN
AT+GAPDISCONNECT
AT+GAPDEVNAME
AT+GAPDELBONDS
AT+GAPINTERVALS
AT+GAPSTARTADV
AT+GAPSTOPADV
AT+GAPSETADVDATA
BLE GATT
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AT+DBGMEMRD
AT+DBGNVMRD
AT+DBGSTACKSIZE
AT+DBGSTACKDUMP
History
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118
GATT Limitations
AT+GATTCLEAR
AT+GATTADDSERVICE
AT+GATTADDCHAR
AT+GATTCHAR
AT+GATTLIST
AT+GATTCHARRAW
Debug
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111
Version
Version
Version
Version
Version
Version
Version
Version
Version
131
0.7.7
0.7.0
0.6.7
0.6.6
0.6.5
0.6.2
0.5.0
0.4.7
0.3.0
GATT Service Details
138
• UART Service
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UART Service
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• Characteristics
• TX (0x0002)
• RX (0x0003)
Software Resources
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Bluefruit LE Client Apps and Libraries
Bluefruit LE Connect (Android/Java)
Bluefruit LE Connect (iOS/Swift)
Bluefruit LE Connect for OS X (Swift)
Bluefruit LE Command Line Updater for OS X (Swift)
Deprecated: Bluefruit Buddy (OS X)
ABLE (Cross Platform/Node+Electron)
Bluefruit LE Python Wrapper
Debug Tools
AdaLink (Python)
Adafruit nRF51822 Flasher (Python)
BLE FAQ
146
Device Recovery
157
• How to Recover a Bluefruit Board
• Still Having Problems?
Downloads
160
• Files
• Schematic
• Board Layout
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Introduction
Would you like to add powerful and easy-to-use Bluetooth Low Energy to your robot,
art or other electronics project? Heck yeah! With BLE now included in modern smart
phones and tablets, its fun to add wireless connectivity. So what you really need is the
new Adafruit Bluefruit LE UART Friend!
The Bluefruit LE UART Friend makes it easy to add Bluetooth Low Energy connectivity
to anything with a hardware or software serial port. We even have nice hardware flow
control so you won't have to think about losing data. Connect to your Arduino or other
microcontroller or even just a standard FTDI cable for debugging and testing.
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This multi-function module can do quite a lot! For most people, they'll be very happy
to use the standard Nordic UART RX/TX connection profile. In this profile, the Bluefruit
acts as a data pipe, that can 'transparently' transmit back and forth from your iOS or
Android device. You can use our iOS App (https://adafru.it/iCi) or Android App (https://
adafru.it/f4G), or write your own to communicate with the UART service (https://
adafru.it/iCF).
So it's a Fancy Pants Wireless UART Adapter?
The board is capable of much more than just sending strings over the air! Thanks to
an easy to learn AT command set (https://adafru.it/iCG), you have full control over how
the device behaves, including the ability to define and manipulate your own GATT
Services and Characteristics (https://adafru.it/iCH), or change the way that the device
advertises itself for other Bluetooth Low Energy devices to see. You can also use the
AT commands to query the die temperature, check the battery voltage, and more,
check the connection RSSI or MAC address, and tons more. Really, way too long to list
here!
Download our free Android/iOS app and you're ready to
rock!
Using our Bluefruit iOS App (https://adafru.it/iCi) or Android App (https://adafru.it/f4G),
you can quickly get your project prototyped by using your iOS or Android phone/
tablet as a controller. We have a color picker (https://adafru.it/iCI), quaternion/
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accelerometer/gyro/magnetometer or location (GPS) (https://adafru.it/iCI), and an 8button control game pad (https://adafru.it/iCI).
You can do a lot more too!
• The Bluefruit can also act like an HID Keyboard (https://adafru.it/iCJ) (for devices
that support BLE HID)
• Can become a BLE Heart Rate Monitor (https://adafru.it/iCK) (a standard profile
for BLE) - you just need to add the pulse-detection circuitry
• Turn it into a UriBeacon (https://adafru.it/iCL), the Google standard for Bluetooth
LE beacons. Just power it and the 'Friend will bleep out a URL to any nearby
devices with the UriBeacon app installed.
• Built in over-the-air bootloading capability so we can keep you updated with the
hottest new firmware. (https://adafru.it/iCM) Use any Android or iOS device to
get updates and install them!
Why Use Adafruit's Module?
There are plenty of BLE modules out there, with varying quality on the HW design as
well as the firmware.
One of the biggest advantages of the Adafruit Bluefruit LE family is that we wrote all
of the firmware running on the devices ourselves from scratch.
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We control every line of code that runs on our modules ... and so we aren't at the
mercy of any third party vendors who may or may not be interested in keeping their
code up to date or catering to our customer's needs.
Because we control everything about the product, we add features that are important
to our customers, can solve any issues that do come up without begging any 3rd
parties, and we can even change Bluetooth SoCs entirely if the need ever arises!
Technical Specifications
• ARM Cortex M0 core running at 16MHz
• 256KB flash memory
• 32KB SRAM
• Peak current draw
• Transport: UART @ 9600 baud with HW flow control (CTS+RTS required!)
• 5V-safe inputs (Arduino Uno friendly, etc.)
• On-board 3.3V voltage regulation
• Bootloader with support for safe OTA firmware updates
• Easy AT command set to get up and running quickly
Pinouts
HW flow control (CTS+RTS) should always be used with the nRF51822. The UART
peripheral block is designed in a way that more or less requires HW flow control
for reliable UART communication, with a very small internal buffer and tight
timing limitations due to the SoftDevice architecture (Nordic's proprietary
Bluetooth Low Energy stack).
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Power Pins
• VIN: This is the power supply for the module, supply with 3.3-16V power supply
input. This will be regulated down to 3.3V to run the chip
• GND: The common/GND pin for power and logic
UART Pins
• TXO - This is the UART Transmit pin out of the breakout (Bluefruit LE --> MCU),
it's at 3.3V logic level.
• RXI - This is the UART Receive pin into the breakout (MCU --> Bluefruit LE). This
has a logic level shifter on it, you can use 3-5V logic.
• CTS - Clear to Send hardware flow control pin into the the breakou (MCU -->
Bluefruit LE). Use this pin to tell the Bluefruit that it can send data back to the
microcontroller over the TXO pin. This pin is pulled high by default and must be
set to ground in order to enable data transfer out! If you do not need hardware
flow control, tie this pin to ground it is a level shifted pin, you can use 3-5V logic
• RTS - Read to Send flow control pin out of the module (Bluefruit LE --> MCU).
This pin will be low when its fine to send data to the Bluefruit. In general, at
9600 baud we haven't seen a need for this pin, but you can watch it for full flow
control! This pin is 3.3V out
Other Pins
• MOD: Mode Selection. The Bluefruit has two modes, Command and Data. You
can keep this pin disconnected, and use the slide switch to select the mode. Or,
you can control the mode by setting this pin voltage, it will override the switch
setting! High = Command Mode, Low = UART/DATA mode. This pin is level
shifted, you can use 3-5V logic
• DFU: Setting this pin low when you power the device up will force the Bluefruit
LE module to enter a special firmware update mode to update the firmware over
the air. Once the device is powered up, this pin can also be used to perform a
factory reset. Wire the pin to GND for >5s until the two LEDs start to blink, then
release the pin (set it to 5V or logic high) and a factory reset will be performed.
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Reverse Side Breakouts
On the back we also have a few breakouts!
Opt VBat: If you fancy, you can solder on a JST 2-PH connector (http://adafru.it/1769),
this will let you easily plug in a Lithium Ion or other battery pack. This connector pad
is diode protected so you can use both Vin and VBat and the regulator will
automatically switch to the higher voltage
Opt. 32 KHz: If you're doing some funky low power work, we wanted to give you the
option of solderin in a 32khz oscillator. (https://adafru.it/f4U)Our firmware doesn't
support it yet but its there!
SWC: This is the SWD clock pin, 3v logic - for advanced hackers!
SWD: This is the SWD data pin, 3v logic - for advanced hackers!
3Vo: This is the output from the 3V regulator, for testing and also if you really need
regulated 3V, up to 250mA available
FCR: This is the factory reset pin. When all else fails and you did something to really
weird out your module, tie this pad to ground while powering up the module and it
will factory reset. You should try the DFU reset method first tho (see that tutorial page)
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Assembly
Prepare the header strip:
Cut the strip to length if necessary. It will
be easier to solder if you insert it into a
breadboard - long pins down
Add the breakout board:
Place the breakout board over the pins so
that the short pins poke through the
breakout pads
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And Solder!
Be sure to solder all pins for reliable
electrical contact.
Solder the longer power/data strip first
(For tips on soldering, be sure to check out
our Guide to Excellent Soldering (https://
adafru.it/aTk)).
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You're done! Check your solder joints
visually and continue onto the next steps
Wiring
You can use the Bluefruit LE UART friend with any microcontroller with 3 or 5V logic.
Here we will demonstrate software serial with an Arduino UNO and hardware serial
with an Arduino MEGA. Depending on whether your microcontroller has a hardware
or software UART, adjust pins as necessary!
Wiring for Arduino Uno
To connect the Bluefruit LE UART Friend to your Arduino Uno using the default pinout
in our sample sketches, connect the pins up as follows:
• MOD to Pin 12
• CTS to Pin 11
• TXO to Pin 10
• RXI to Pin 9
• VIN to 5V
• RTS to Pin 8
• GND to GND
The wiring diagram below shows how this might look on your system:
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All of these pins are 'flexible' and you can change them around as necessary after you
get your setup running nicely, but we recommend starting out with our default wiring.
Wiring for an Arduino MEGA
This is the recommended approach on an Arduino MEGA. This should also work for
an Arduino Micro, Leonardo, or any other board with a hardware serial port. To
connect the Bluefruit LE UART Friend to an Arduino MEGA (Serial1 in this case), use
the following pinout and make sure you've selected HW UART as the constructor in
your sample sketches (they default to SW Serial):
• TX1 to RXI
• RX1 to TXO
• +5V to VIN
• GND to GND
• Also connect CTS on the Bluefruit LE Module to GND
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The HW Serial constructor can be seen below, and should be uncommented in the
sample sketches:
/* ...or hardware serial, which does not need the RTS/CTS pins. Uncomment this line
*/
Adafruit_BluefruitLE_UART ble(BLUEFRUIT_HWSERIAL_NAME, BLUEFRUIT_UART_MODE_PIN);
Not Connecting? Try a Power Cycle
If the example sketch does not appear to connect, like this:
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Then double check your wiring and make sure the slide switch is in the CMD position.
If that all seems OK, you can also try power cycling the Bluefruit LE UART Friend.
Simply remove the 5V wire for a sec and then reconnect it. Then try running the
sketch again. Hopefully it'll start responding then.
Wiring for an FTDI Cable
Since the UART Friend is, well, a serial port, you can use an FTDI Friend or cable to
quickly connect using any serial console. You won't get MODE or DFU connections, so
don't forget to flick the mode switch as necessary if you want to be in a particular
mode.
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Simply insert an FTDI cable directly into the Bluefruit LE UART Friend header by using
the six pins in the middle, being careful to align the power pins up correctly (the red
wire to VIN and the black wire to GND):
Factory Reset
There are several methods that you can use to perform a factory reset on your
Bluefruit LE module if something gets misconfigured, or to delete persistent changes
like UriBeacon or advertising payload changes, etc.
These methods are the same for both UART and SPI versions of Bluefruit LE
Factory Reset via DFU Pin
If you hold the DFU pin low (set the pin to GND) for >5 seconds, the red and blue
LEDs next to the module will start blinking and the device will perform a factory reset
as soon as you release the DFU pin (disconnecting it from GND).
If you have a DFU button instead of a pin, just hold the button down.
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FactoryReset Sample Sketch
There is a FactoryReset sample sketch in the Adafruit Bluefruit LE library, which can
be access in the File > Examples > Adafruit_BluefruitLE_nRF51 folder (See the
Software section of this tutorial (https://adafru.it/iCj) for instructions on installing the
library):
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Upload this sketch and open the Serial Monitor and it should perform a factory reset
for you:
AT+FACTORYRESET
You can also perform a factory reset by sending the AT+FACTORYRESET command to
your Bluefruit LE module in your favorite terminal emulator or using the ATCommand (
https://adafru.it/iCk) example sketch.
AT+FACTORYRESET
OK
This command will also cause the device to reset.
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Factory Reset via FCTR Test Pad
On the bottom of the Bluefruit LE Friend board or shields there is a test pad or pin
that exposes the Factory Reset pin on the modules (marked FCR or F.RST). Setting
this pad low when the device is powered up will cause a factory reset at startup.
DFU Updates
We're constantly working on the Bluefruit LE firmware to add new features, and keep
up to date with what customers need and want.
To make sure you stay up to date with those changes, we've included an easy to use
over the air updater on all of our nRF51 based Bluefruit LE modules.
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Adafruit Bluefruit LE Connect
Updating your Bluefruit LE device to the latest firmware is as easy as installing Adafrui
t's Bluefruit LE Connect application (https://adafru.it/f4G) (Android) from the Google
Play Store or Bluefruit LE Connect for iOS (https://adafru.it/f4H) from the Apple App
Store.
Any time a firmware update is available, the application will propose to download the
latest binaries and take care of all the details of transferring them to your Bluefruit
device, ans shown in the video below:
Current Measurements
The following tables give you an idea of the average current draw in three different
operating modes with the Bluefruit LE UART Friend:
• Fast Advertising Mode (the first 30 seconds after power up)
• Slow Advertising Mode (>30s since power up)
• Connected Mode (using the UART profile in this case)
Test Conditions
The board was powered from a fully charged 1200mAh 4.2V LIPO (https://adafru.it/
dyW) cell running at 4.2V. Power efficiency will generally increase as the LIPO battery
voltage drops, so 4.2V should be considered a worst case scenario.
• Power Supply: 1200mAh 4.2V LIPO Cell (at 4.2V)
• Firmware: 0.6.2
Fast Advertising Mode
The first 30 seconds that the Bluefruit LE UART Friend is powered up it will enter 'Fast
Advertising Mode', which sends an advertising packet once every 100ms.
• Average Current: 1.44mA
• Peak Current: 13.5mA
• Expected Battery Life: 832 hours (~34.6 days)
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The MODE LEDs can be seen blinking in regular intervals as the three
rectangular bumps at the bottom of the chart.
Slow Advertising Mode
After 30 seconds the Bluefruit LE UART Friend will enter 'Slow Advertising Mode',
which sends an advertising packet once every 546.25ms.
• Average Current: 1.25mA
• Peak Current: 13.5mA
• Expected Battery Life: 956 hours (~40 days)
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Connected Mode (UART)
The following measurements illustrate the average current draw in connected mode
(with the connected LED enabled). UART mode was used as a test case.
• Average Current: 1.86mA
• Peak Current: 15.2mA
• Expected Battery Life: 645 hours (~26.8 days)
Software
In order to try out our demos, you'll need to download the Adafruit BLE library for the
nRF51 based modules such as this one (a.k.a. Adafruit_BluefruitLE_nRF51)
You can check out the code here at github, (https://adafru.it/f4V) but its likely easier to
just download by clicking:
Download
Adafruit_BluefruitLE_nRF51
https://adafru.it/f4W
Rename the uncompressed folder Adafruit_BluefruitLE_nRF51 and check that the Ada
fruit_BluefruitLE_nRF51 folder contains Adafruit_BLE.cpp and Adafruit_BLE.h (as well
as a bunch of other files)
Place the Adafruit_BluefruitLE_nRF51 library folder your arduinosketchfolder/libraries/
folder.
You may need to create the libraries subfolder if its your first library. Restart the IDE.
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We also have a great tutorial on Arduino library installation at:
http://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use (https://
adafru.it/aYM)
After restarting, check that you see the library folder with examples:
Configuration!
Before you start uploading any of the example sketches, you'll need to
CONFIGURE the Bluefruit interface - there's a lot of options so pay close
attention!
Which board do you have?
There's a few products under the Bluefruit name:
If you are using the Bluefruit LE Shield
then you have an SPI-connected
NRF51822 module. You can use this with
Atmega328 (Arduino UNO or compatible),
ATmega32u4 (Arduino Leonardo,
compatible) or ATSAMD21 (Arduino Zero,
compatible) and possibly others.
Your pinouts are Hardware SPI, CS = 8,
IRQ = 7, RST = 4
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Bluefruit Micro or Feather
32u4 Bluefruit
If you have a Bluefruit Micro or Feather
32u4 Bluefruit LE then you have an
ATmega32u4 chip with Hardware SPI, CS =
8, IRQ = 7, RST = 4
Feather M0 Bluefruit LE
If you have a Feather M0 Bluefruit LE then
you have an ATSAMD21 chip with
Hardware SPI, CS = 8, IRQ = 7, RST = 4
Bluefruit LE SPI Friend
If you have a stand-alone module, you
have a bit of flexibility with wiring however
we strongly recommend Hardware SPI, CS
= 8, IRQ = 7, RST = 4
You can use this with just about any
microcontroller with 5 or 6 pins
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Bluefruit LE UART Friend or
Flora BLE
If you have a stand-alone UART module
you have some flexibility with wiring.
However we suggest hardware UART if
possible. You will likely need to use the
flow control CTS pin if you are not using
hardware UART. There's also a MODE pin
You can use this with just about any
microcontroller with at least 3 pins, but
best used with a Hardware Serial/UART
capable chip!
Configure the Pins Used
You'll want to check the Bluefruit Config to set up the pins you'll be using for UART or
SPI
Each example sketch has a secondary tab with configuration details. You'll want to
edit and save the sketch to your own documents folder once set up.
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Common settings:
You can set up how much RAM to set aside for a communication buffer and whether
you want to have full debug output. Debug output is 'noisy' on the serial console but
is handy since you can see all communication between the micro and the BLE
//
---------------------------------------------------------------------------------------------// These settings are used in both SW UART, HW UART and SPI mode
//
---------------------------------------------------------------------------------------------#define BUFSIZE
128
// Size of the read buffer for
incoming data
#define VERBOSE_MODE
true // If set to 'true' enables debug
output
Software UART
If you are using Software UART, you can set up which pins are going to be used for
RX, TX, and CTS flow control. Some microcontrollers are limited on which pins can be
used! Check the SoftwareSerial library documentation for more details
// SOFTWARE UART SETTINGS
#define BLUEFRUIT_SWUART_RXD_PIN
#define BLUEFRUIT_SWUART_TXD_PIN
#define BLUEFRUIT_UART_CTS_PIN
#define BLUEFRUIT_UART_RTS_PIN
9
10
11
-1
//
//
//
//
Required for software serial!
Required for software serial!
Required for software serial!
Optional, set to -1 if unused
Hardware UART
If you have Hardware Serial, there's a 'name' for it, usually Serial1 - you can set that up
here:
// HARDWARE UART SETTINGS
#ifdef Serial1
// this makes it not complain on compilation if there's no Serial1
#define BLUEFRUIT_HWSERIAL_NAME
Serial1
#endif
Mode Pin
For both hardware and software serial, you will likely want to define the MODE pin.
There's a few sketches that dont use it, instead depending on commands to set/unset
the mode. Its best to use the MODE pin if you have a GPIO to spare!
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#define BLUEFRUIT_UART_MODE_PIN
12
// Set to -1 if unused
SPI Pins
For both Hardware and Software SPI, you'll want to set the CS (chip select) line, IRQ
(interrupt request) line and if you have a pin to spare, RST (Reset)
// SHARED SPI SETTINGS
#define BLUEFRUIT_SPI_CS
#define BLUEFRUIT_SPI_IRQ
#define BLUEFRUIT_SPI_RST
if unused
8
7
4
// Optional but recommended, set to -1
Software SPI Pins
If you don't have a hardware SPI port available, you can use any three pins...its a tad
slower but very flexible
// SOFTWARE SPI SETTINGS
#define BLUEFRUIT_SPI_SCK
#define BLUEFRUIT_SPI_MISO
#define BLUEFRUIT_SPI_MOSI
13
12
11
Refer to the table above to determine whether you have SPI or UART controlled
Bluefruits!
Select the Serial Bus
Once you've configured your pin setup in the BluefruitConfig.h file, you can now
check and adapt the example sketch.
The Adafruit_BluefruitLE_nRF51 library supports four different serial bus options,
depending on the HW you are using: SPI both hardware and software type, and UART
both hardware and software type.
UART Based Boards (Bluefruit LE UART Friend & Flora
BLE)
This is for Bluefruit LE UART Friend & Flora BLE boards. You can use either software
serial or hardware serial. Hardware serial is higher quality, and less risky with respect
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to losing data. However, you may not have hardware serial available! Software serial
does work just fine with flow-control and we do have that available at the cost of a
single GPIO pin.
For software serial (Arduino Uno, Adafruit Metro) you should uncomment the software
serial contructor below, and make sure the other three options (hardware serial & SPI)
are commented out.
// Create the bluefruit object, either software serial...uncomment these lines
SoftwareSerial bluefruitSS = SoftwareSerial(BLUEFRUIT_SWUART_TXD_PIN,
BLUEFRUIT_SWUART_RXD_PIN);
Adafruit_BluefruitLE_UART ble(bluefruitSS, BLUEFRUIT_UART_MODE_PIN,
BLUEFRUIT_UART_CTS_PIN, BLUEFRUIT_UART_RTS_PIN);
For boards that require hardware serial (Adafruit Flora, etc.), uncomment the
hardware serial constructor, and make sure the other three options are commented
out
/* ...or hardware serial, which does not need the RTS/CTS pins. Uncomment this line
*/
Adafruit_BluefruitLE_UART ble(BLUEFRUIT_HWSERIAL_NAME, BLUEFRUIT_UART_MODE_PIN);
SPI Based Boards (Bluefruit LE SPI Friend)
For SPI based boards, you should uncomment the hardware SPI constructor below,
making sure the other constructors are commented out:
/* ...hardware SPI, using SCK/MOSI/MISO hardware SPI pins and then user selected CS/
IRQ/RST */
Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ,
BLUEFRUIT_SPI_RST);
If for some reason you can't use HW SPI, you can switch to software mode to bit-bang
the SPI transfers via the following constructor:
/* ...software SPI, using SCK/MOSI/MISO user-defined SPI pins and then user
selected CS/IRQ/RST */
Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_SCK, BLUEFRUIT_SPI_MISO,
BLUEFRUIT_SPI_MOSI, BLUEFRUIT_SPI_CS,
BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);
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ATCommand
The ATCommand example allows you to execute AT commands from your sketch, and
see the results in the Serial Monitor. This can be useful for debugging, or just testing
different commands out to see how they work in the real world. It's a good one to
start with!
Opening the Sketch
To open the ATCommand sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select atcommand:
This will open up a new instance of the example in the IDE, as shown below:
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Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If using software or hardware Serial UART:
• This tutorial does not need to use the MODE pin, make sure you have the mode
switch in CMD mode if you do not configure & connect a MODE pin
• Don't forget to also connect the CTS pin on the Bluefruit to ground if you are not
using it! (The Flora has this already done)
Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
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To send an AT command to the Bluefruit LE module, enter the command in the textbox
at the top of the Serial Monitor and click the Send button:
The response to the AT command will be displayed in the main part of the Serial
Monitor. The response from 'ATI' is shown below:
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You can do pretty much anything at this prompt, with the AT command set. Try AT+HE
LP to get a list of all commands, and try out ones like AT+HWGETDIETEMP (get
temperature at the nRF51822 die) and AT+HWRANDOM (generate a random number)
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BLEUart
The BLEUart example sketch allows you to send and receive text data between the
Arduino and a connected Bluetooth Low Energy Central device on the other end
(such as you mobile phone using the Adafruit Bluefruit LE Connect application for And
roid (https://adafru.it/f4G) or iOS (https://adafru.it/f4H) in UART mode).
Opening the Sketch
To open the ATCommand sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select bleuart_cmdmode:
This will open up a new instance of the example in the IDE, as shown below:
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Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If using software or hardware Serial UART:
• This tutorial does not need to use the MODE pin, make sure you have the mode
switch in CMD mode if you do not configure & connect a MODE pin
• Don't forget to also connect the CTS pin on the Bluefruit to ground if you are not
using it! (The Flora has this already done)
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Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
Once you see the request, use the App to connect to the Bluefruit LE module in UART
mode so you get the text box on your phone
Any text that you type in the box at the top of the Serial Monitor will be sent to the
connected phone, and any data sent from the phone will be displayed in the serial
monitor:
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You can see the incoming string here in the Adafruit Bluefruit LE Connect app below
(iOS in this case):
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The response text ('Why hello, Arduino!') can be seen below:
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HIDKeyboard
The HIDKeyboard example shows you how you can use the built-in HID keyboard AT
commands to send keyboard data to any BLE-enabled Android or iOS phone, or other
device that supports BLE HID peripherals.
Opening the Sketch
To open the ATCommand sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select hidkeyboard:
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This will open up a new instance of the example in the IDE, as shown below:
Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If using software or hardware Serial UART:
• This tutorial does not need to use the MODE pin, make sure you have the mode
switch in CMD mode!
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• Don't forget to also connect the CTS pin on the Bluefruit to ground if you are not
using it! (The Flora has this already done)
Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
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To send keyboard data, type anything into the textbox at the top of the Serial Monitor
and click the Send button.
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Bonding the HID Keyboard
Before you can use the HID keyboard, you will need to 'bond' it to your phone or PC.
The bonding process establishes a permanent connection between the two devices,
meaning that as soon as your phone or PC sees the Bluefruit LE module again it will
automatically connect.
The exact procedures for bonding the keyboard will varying from one platform to
another.
When you no longer need a bond, or wish to bond the Bluefruit LE module to
another device, be sure to delete the bonding information on the phone or PC,
otherwise you may not be able to connect on a new device!
Android
To bond the keyboard on a Bluetooth Low Energy enabled Android device, go to
the Settings application and click the Bluetooth icon.
These screenshots are based on Android 5.0 running on a Nexus 7 2013. The
exact appearance may vary depending on your device and OS version.
Inside the Bluetooth setting panel you should see the Bluefruit LE module advertising
itself as Bluefruit Keyboard under the 'Available devices' list:
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Tapping the device will start the bonding process, which should end with the Bluefruit
Keyboard device being moved to a new 'Paired devices' list with 'Connected' written
underneath the device name:
To delete the bonding information, click the gear icon to the right of the device name
and the click the Forget button:
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iOS
To bond the keyboard on an iOS device, go to the Settings application on your phone,
and click the Bluetooth menu item.
The keyboard should appear under the OTHER DEVICES list:
Once the bonding process is complete the device will be moved to the MY DEVICES
category, and you can start to use the Bluefruit LE module as a keyboard:
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To unbond the device, click the 'info' icon and then select the Forget this Device
option in the menu:
OS X
To bond the keyboard on an OS X device, go to the Bluetooth Preferences window
and click the Pair button beside the Bluefruit Keyboard device generated by this
example sketch:
To unbond the device once it has been paired, click the small 'x' icon beside Bluefruit
Keyboard:
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... and then click the Remove button when the confirmation dialogue box pops up:
Controller
The Controller sketch allows you to turn your BLE-enabled iOS or Android device in a
hand-held controller or an external data source, taking advantage of the wealth of
sensors on your phone or tablet.
You can take accelerometer or quaternion data from your phone, and push it out to
your Arduino via BLE, or get the latest GPS co-ordinates for your device without
having to purchase (or power!) any external HW.
Opening the Sketch
To open the Controller sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select controller:
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This will open up a new instance of the example in the IDE, as shown below:
Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If using software or hardware Serial UART:
• This tutorial will also be easier to use if you wire up the MODE pin, you can use
any pin but our tutorial has pin 12 by default. You can change this to any pin. If
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you do not set the MODE pin then make sure you have the mode switch in CMD
mode
• If you are using a Flora or otherwise don't want to wire up the Mode pin, set the
BLUEFRUIT_UART_MODE_PIN to -1 in the configuration tab so that the sketch
will use the +++ method to switch between Command and Data mode!
• Don't forget to also connect the CTS pin on the Bluefruit to ground if you are not
using it! (The Flora has this already done)
Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
Using Bluefruit LE Connect in Controller
Mode
Once the sketch is running you can open Adafruit's Bluefruit LE Connect application
(available for Android (https://adafru.it/f4G) or iOS (https://adafru.it/f4H)) and use the C
ontroller application to interact with the sketch. (If you're new to Bluefruit LE Connect,
have a look at our dedicated Bluefruit LE Connect learning guide (https://adafru.it/
iCm).)
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On the welcome screen, select the Adafruit Bluefruit LE device from the list of BLE
devices in range:
Then from the activity list select Controller:
This will bring up a list of data points you can send from your phone or tablet to your
Bluefruit LE module, by enabling or disabling the appropriate sensor(s).
Streaming Sensor Data
You can take Quaternion (absolute orientation), Accelerometer, Gyroscope,
Magnetometer or GPS Location data from your phone and send it directly to your
Arduino from the Controller activity.
By enabling the Accelerometer field, for example, you should see accelerometer data
update in the app:
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The data is parsed in the example sketch and output to the Serial Monitor as follows:
Accel
Accel
Accel
Accel
Accel
0.20-0.51
0.22-0.50
0.25-0.51
0.21-0.47
0.27-0.48
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-0.76
-0.83
-0.83
-0.76
-0.82
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Note that even though we only print 2 decimal points, the values are received from
the App as a full 4-byte floating point.
Control Pad Module
You can also use the Control Pad Module to capture button presses and releases by
selecting the appropriate menu item:
This will bring up the Control Pad panel, shown below:
Button presses and releases will all be logged to the Serial Monitor with the ID of the
button used:
Button
Button
Button
Button
8
8
3
3
pressed
released
pressed
released
Color Picker Module
You can also send RGB color data via the Color Picker module, which presents the
following color selection dialogue:
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This will give you Hexadecimal color data in the following format:
RGB #A42FFF
You can combine the color picker and controller sample sketches to make colorconfigurable animations triggered by buttons in the mobile app-- very handy for
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wearables! Download this combined sample code (configured for Feather but easy to
adapt to FLORA, BLE Micro, etc.) to get started:
feather_bluefruit_neopixel_animation_controller.zip
https://adafru.it/kzF
HeartRateMonitor
The HeartRateMonitor example allows you to define a new GATT Service and
associated GATT Characteristics, and update the characteristic values using standard
AT commands.
Opening the Sketch
To open the ATCommand sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select heartratemonitor:
This will open up a new instance of the example in the IDE, as shown below:
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Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If Using Hardware or Software UART
This tutorial does not need to use the MODE pin, make sure you have the mode
switch in CMD mode if you do not configure & connect a MODE pin
This demo uses some long data transfer strings, so we recommend defining and
connecting both CTS and RTS to pins, even if you are using hardware serial.
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If you are using a Flora or just dont want to connect CTS or RTS, set the pin #define's
to -1 and Don't forget to also connect the CTS pin on the Bluefruit to ground! (The
Flora has this already done)
If you are using RTS and CTS, you can remove this line below, which will slow down
the data transmission
// this line is particularly required for Flora, but is a good idea
// anyways for the super long lines ahead!
ble.setInterCharWriteDelay(5); // 5 ms
Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
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If you open up an application on your mobile device or laptop that support the
standard Heart Rate Monitor Service (https://adafru.it/f4I), you should be able to see
the heart rate being updated in sync with the changes seen in the Serial Monitor:
nRF Toolbox HRM Example
The image below is a screenshot from the free nRF Toolbox (https://adafru.it/e9M) app
lication from Nordic on Android (also available on iOS (https://adafru.it/f4J)), showing
the incoming Heart Rate Monitor data:
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CoreBluetooth HRM Example
The image below is from a freely available CoreBluetooth sample application (https://
adafru.it/f4K) from Apple showing how to work with Bluetooth Low Energy services
and characteristics:
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UriBeacon
The UriBeacon example shows you how to use the built-in UriBeacon AT commands
to configure the Bluefruit LE module as a UriBeacon advertiser, following Google's
Physical Web UriBeacon (https://adafru.it/edk) specification.
Opening the Sketch
To open the ATCommand sketch, click on the File > Examples >
Adafruit_BluefruitLE_nRF51 folder in the Arduino IDE and select uribeacon:
This will open up a new instance of the example in the IDE, as shown below. You can
edit the URL that the beacon will point to, from the default http://www.adafruit.com or
just upload as is to test
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Configuration
Check the Configuration! page earlier to set up the sketch for Software/Hardware
UART or Software/Hardware SPI. The default is hardware SPI
If using software or hardware Serial UART:
• This tutorial does not need to use the MODE pin, make sure you have the mode
switch in CMD mode if you do not configure & connect a MODE pin
• Don't forget to also connect the CTS pin on the Bluefruit to ground if you are not
using it! (The Flora has this already done)
Running the Sketch
Once you upload the sketch to your board (via the arrow-shaped upload icon), and
the upload process has finished, open up the Serial Monitor via Tools > Serial Monitor,
and make sure that the baud rate in the lower right-hand corner is set to 115200:
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At this point you can open the Physical Web Application for Android (https://adafru.it/
edi) or for iOS (https://adafru.it/edj), and you should see a link advertising Adafruit's
website:
HALP!
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When using the Bluefruit Micro or a Bluefruit LE with
Flora/Due/Leonardo/Micro the examples dont run?
We add a special line to setup() to make it so the Arduino will halt until it sees
you've connected over the Serial console. This makes debugging great but makes
it so you cannot run the program disconnected from a computer.
Solution? Once you are done debugging, remove these two lines from setup()
while (!Serial);
delay(500);
I can't seem to "Find" the Bluefruit LE!
Getting something like this?
For UART/Serial Bluefruits:
• Check you have the MODE switch in CMD and the MODE pin not wired to
anything if it isnt used!
• If you are trying to control the MODE from your micro, make sure you set the
MODE pin in the sketch
• Make sure you have RXI and TXO wired right! They are often swapped by
accident
• Make sure CTS is tied to GND if you are using hardware serial and not using
CTS
• Check the MODE red LED, is it blinking? If its blinking continuously, you might be
in DFU mode, power cycle the module!
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• If you are using Hardware Serial/Software Serial make sure you know which one
and have that set up
If using SPI Bluefruit:
• Make sure you have all 5 (or 6) wires connected properly.
• If using hardware SPI, you need to make sure you're connected to the hardware
SPI port, which differs depending on the main chipset.
If using Bluefruit Micro:
• Make sure you change the RESET pin to #4 in any Config file. Also be sure you
are using hardware SPI to connect!
Data Mode
By placing the BLEFriend module in 'UART Data' mode (set the mode selection switch
to UART or setting the MODE pin to gound) you can use the module as a 'transparent
UART connection' to the Bluefruit app. This makes data transfer super simple. Data is
sent to the app when any 9600 baud data is received on the RXI pin and any data
from the app is automatically transmitted via the TXO pin
In order to keep from overloading your microcontroller, you can use the flow control
pins. Keep the CTS pin high until you're ready for more data, then ground it to let the
Bluefruit module know you're ready for more data!
This mode uses hardware flow control! You must set the CTS pin to ground in
order to enable the TXO pin, so if you're wondering why its not sending data,
check that CTS is being used right!
You can determine if you are in Data Mode by looking at the mode LED. It should
blink two times followed by a three second pause, as shown below:
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You can then connect the the app in UART mode and send/receive data transparently
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Switching Command/Data Mode via +++
On either side of the connection (via the Arduino Uno or in your mobile app), you can
dynamically switch between command and data mode by sending the "+++\n" string,
as detailed in the +++ command summary (https://adafru.it/iCN).
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If you start in data mode, you can send text for example, with "+++\nATI\n+++\n", which
will cause the Bluefruit LE module to switch to command mode, execute the ATI
command, and then switch back to data mode.
The +++ command can be sent from either side, making it possible to execute
commands from the mobile application as well as on the Bluefruit LE side.
# Start in Data Mode
> Hello, World! Data mode!
# Send command to switch modes
> +++
# Bluefruit LE module switches to CMD mode
# Send ATI command and wait for the response
> ATI
< BLEFRIEND
< nRF51822 QFAAG00
< B122AAC33F3D2296
< 0.6.2
< 0.6.2
< May 01 2015
< OK
# Switch back to DATA mode
> +++
< OK
# We're back in data mode now
Welcome back!
Command Mode
By placing the BLEFriend module in 'Command' mode (set the mode selection switch
to CMD or setting the MODE pin to a high voltage) you can enter a variety of Hayes
AT style commands to configure the device or retrieve basic information about the
module of BLE connection.
In order to keep from overloading your microcontroller, you can use the flow control
pins. Keep the CTS pin high until you're ready for more data, then ground it to let the
Bluefruit module know you're ready for more data!
This mode uses hardware flow control! You must set the CTS pin to ground in
order to enable the TXO pin, so if you're wondering why its not responding to
commands, check that CTS is being used right!
You can determine if you are in Command Mode by looking at the mode LED. It
should blink three times followed by a three second pause, as shown below:
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Hayes/AT Commands
When operating in command mode, the Bluefruit LE Pro modules use a Hayes ATstyle command set (https://adafru.it/ebJ)to configure the device.
The advantage of an AT style command set is that it's easy to use in machine to
machine communication, while still being somewhat user friendly for humans.
Test Command Mode '=?'
'Test' mode is used to check whether or not the specified command exists on the
system or not.
Certain firmware versions or configurations may or may not include a specific
command, and you can determine if the command is present by taking the command
name and appending '=?' to it, as shown below
AT+BLESTARTADV=?
If the command is present, the device will reply with 'OK'. If the command is not
present, the device will reply with 'ERROR'.
AT+BLESTARTADV=?
OK\r\n
AT+MISSINGCMD=?
ERROR\r\n
Write Command Mode '=xxx'
'Write' mode is used to assign specific value(s) to the command, such as changing the
radio's transmit power level using the command we used above.
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To write a value to the command, simple append an '=' sign to the command followed
by any paramater(s) you wish to write (other than a lone '?' character which will be
interpreted as test mode):
AT+BLEPOWERLEVEL=-8
If the write was successful, you will generally get an 'OK' response on a new line, as
shown below:
AT+BLEPOWERLEVEL=-8
OK\r\n
If there was a problem with the command (such as an invalid parameter) you will get
an 'ERROR' response on a new line, as shown below:
AT+BLEPOWERLEVEL=3
ERROR\r\n
Note: This particular error was generated because '3' is not a valid value for the
AT+BLEPOWERLEVEL command. Entering '-4', '0' or '4' would succeed since these
are all valid values for this command.
Execute Mode
'Execute' mode will cause the specific command to 'run', if possible, and will be used
when the command name is entered with no additional parameters.
AT+FACTORYRESET
You might use execute mode to perform a factory reset, for example, by executing the
AT+FACTORYRESET command as follows:
AT+FACTORYRESET
OK\r\n
NOTE: Many commands will perform the same action whether they are sent to the
command parser in 'execute' or 'read' mode. For example, the following commands
will produce identical results:
AT+BLEGETPOWERLEVEL
-4\r\n
OK\r\n
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AT+BLEGETPOWERLEVEL?
-4\r\n
OK\r\n
If the command doesn't support execute mode, the response will normally be 'ERROR'
on a new line.
Read Command Mode '?'
'Read' mode is used to read the current value of a command.
Not every command supports read mode, but you generally use this to retrieve
information like the current transmit power level for the radio by appending a '?' to the
command, as shown below:
AT+BLEPOWERLEVEL?
If the command doesn't support read mode or if there was a problem with the
request, you will normally get an 'ERROR' response.
If the command read was successful, you will normally get the read results followed
by 'OK' on a new line, as shown below:
AT+BLEPOWERLEVEL?
-4\r\n
OK\r\n
Note: For simple commands, 'Read' mode and 'Execute' mode behave identically.
Dynamically Switching Modes via +++
When operating in Command Mode you can dynamically switch to Data Mode (and
back again) in software via the +++ command (https://adafru.it/iCN). See the full
command description for details.
Standard AT
The following standard Hayes/AT commands are available on Bluefruit LE modules:
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AT
Acts as a ping to check if we are in command mode. If we are in command mode, we
should receive the 'OK' response.
Codebase Revision: 0.3.0
Parameters: None
Output: None
AT
OK
ATI
Displays basic information about the Bluefruit module.
Codebase Revision: 0.3.0
Parameters: None
Output: Displays the following values:
• Board Name
• Microcontroller/Radio SoC Name
• Unique Serial Number
• Core Bluefruit Codebase Revision
• Project Firmware Revision
• Firmware Build Date
• Softdevice, Softdevice Version, Bootloader Version (0.5.0+)
ATI
BLEFRIEND
nRF51822 QFAAG00
FB462DF92A2C8656
0.5.0
0.5.0
Feb 24 2015
S110 7.1.0, 0.0
OK
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Updates:
• Version 0.4.7+ of the firmware adds the chip revision after the chip name if it can
be detected (ex. 'nRF51822 QFAAG00').
• Version 0.5.0+ of the firmware adds a new 7th record containing the softdevice,
softdevice version and bootloader version (ex. 'S110 7.1.0, 0.0').
ATZ
Performs a system reset.
Codebase Revision: 0.3.0
Parameters: None
Output: None
ATZ
OK
ATE
Enables or disables echo of input characters with the AT parser
Codebase Revision: 0.3.0
Parameters: '1' = enable echo, '0' = disable echo
Output: None
# Disable echo support
ATE=0
OK
#Enable echo support
ATE=1
OK
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+++
Dynamically switches between DATA and COMMAND mode without changing the
physical CMD/UART select switch.
When you are in COMMAND mode, entering '+++\n' or '+++\r\n' will cause the module
to switch to DATA mode, and anything typed into the console will go direct to the
BLUE UART service.
To switch from DATA mode back to COMMAND mode, simply enter '+++\n' or '+++\r\n'
again (be sure to include the new line character!), and a new 'OK' response will be
displayed letting you know that you are back in COMMAND mode (see the two 'OK'
entries in the sample code below).
Codebase Revision: 0.4.7
Parameters: None
Output: None
Note that +++ can also be used on the mobile device to send and receive AT
command on iOS or Android, though this should always be used with care.
See the AT+MODESWITCHEN command to control the availability of the +++
command
ATI
BLEFRIEND
nRF51822 QFAAG00
B122AAC33F3D2296
0.4.6
0.4.6
Dec 22 2014
OK
+++
OK
OK
General Purpose
The following general purpose commands are available on all Bluefruit LE modules:
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AT+FACTORYRESET
Clears any user config data from non-volatile memory and performs a factory reset
before resetting the Bluefruit module.
Codebase Revision: 0.3.0
Parameters: None
Output: None
AT+FACTORYRESET
OK
As of version 0.5.0+ of the firmware, you can perform a factory reset by holding
the DFU button down for 10s until the blue CONNECTED LED lights up, and then
releasing the button.
AT+DFU
Forces the module into DFU mode, allowing over the air firmware updates using a
dedicated DFU app on iOS or Android.
Codebase Revision: 0.3.0
Parameters: None
Output: None
The AT parser will no longer responsd after the AT+DFU command is entered,
since normal program execution effectively halts and a full system reset is
performed to start the bootloader code
AT+DFU
OK
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AT+HELP
Displays a comma-separated list of all AT parser commands available on the system.
Codebase Version: 0.3.0
Parameters: None
Output: A comma-separated list of all AT parser commands available on the system.
The sample code below may not match future firmware releases and is provided
for illustration purposes only
AT+HELP
AT+FACTORYRESET,AT+DFU,ATZ,ATI,ATE,AT+DBGMEMRD,AT+DBGNVMRD,AT+HWLEDPOLARITY,AT+HWLED,AT+HWGETD
OK
AT+NVMWRITE
Writes data to the 256 byte user non-volatile memory (NVM) region.
Codebase Version: 0.7.0
Parameters:
• offset: The numeric offset for the first byte from the starting position in the user
NVM
• datatype: Which can be one of STRING (1), BYTEARRAY (2) or INTEGER (3)
• data: The data to write to NVM memory (the exact payload format will change
based on the specified datatype).
Output: Nothing
# Write 32768 as an integer starting at byte 16 in user NVM
AT+NVMWRITE=16,INTEGER,32768
OK
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AT+NVMREAD
Reads data from the 256 byte user non-volatile memory (NVM) region.
Codebase Version: 0.7.0
Parameters:
• offset: The numeric offset for the first byte from the starting position in the user
NVM
• size: The number of bytes to read
• datatype: The type used for the data being read, which is required to properly
parse the data and display it as a response. The value can be one of STRING (1),
BYTEARRAY (2) or INTEGER (3)
Output: The data read back, formatted based on the datatype argument.
# Read an integer back from position 16 in user NVM
AT+NVMREAD=16, 4, INTEGER
32768
OK
AT+MODESWITCHEN
Enables or disables mode switches via the '+++' command on the BLE peripheral of
BLE UART side of the connection.
Codebase Version: 0.7.1
Parameters:
• location: This can be a string, either 'local' or 'ble' indicating which side should
have the '+++' command enabled or disabled, 'local' being the Bluefruit
peripheral and 'ble' being the phone or tablet.
• state: '0' to disable '+++' mode switches, '1' to enable them.
Output: None
By default, '+++' is enabled locally, and disabled in BLE
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# Disable reomte '+++' mode switches
AT+MODESWITCHEN=ble,0
OK
Hardware
The following commands allow you to interact with the low level HW on the Bluefruit
LE module, such as reading or toggling the GPIO pins, performing an ADC conversion
,etc.:
AT+BAUDRATE
Changes the baud rate used by the HW UART peripheral on the nRF51822. Note that
we do not recommend using higher baudrates than 9600 because the nRF51 UART
can drop characters!
Codebase Revision: 0.7.0
Parameters: Baud rate, which must be one of the following values:
• 1200
• 2400
• 4800
• 9600
• 14400
• 19200
• 28800
• 38400
• 57600
• 76800
• 115200
• 230400
• 250000
• 460800
• 921600
• 1000000
Output: The current baud rate
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# Set the baud rate to 115200
AT+BAUDRATE=115200
OK
# Check the current baud rate
AT+BAUDRATE
115200
OK
AT+HWADC
Performs an ADC conversion on the specified ADC pin
Codebase Revision: 0.3.0
Parameters: The ADC channel (0..7)
Output: The results of the ADC conversion
AT+HWADC=0
178
OK
AT+HWGETDIETEMP
Gets the temperature in degree celcius of the BLE module's die. This can be used for
debug purposes (higher die temperature generally means higher current
consumption), but does not corresponds to ambient temperature and can not be used
as a replacement for a normal temperature sensor.
Codebase Revision: 0.3.0
Parameters: None
Output: The die temperature in degrees celcius
AT+HWGETDIETEMP
32.25
OK
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AT+HWGPIO
Gets or sets the value of the specified GPIO pin (depending on the pin's mode).
Codebase Revision: 0.3.0
Parameters: The parameters for this command change depending on the pin mode.
OUTPUT MODE: The following comma-separated parameters can be used when
updating a pin that is set as an output:
• Pin numbers
• Pin state, where:
◦ 0 = clear the pin (logic low/GND)
◦ 1 = set the pin (logic high/VCC)
INPUT MODE: To read the current state of an input pin or a pin that has been
configured as an output, enter the pin number as a single parameter.
Output: The pin state if you are reading an input or checking the state of an input pin
(meaning only 1 parameter is supplied, the pin number), where:
• 0 means the pin is logic low/GND
• 1 means the pin is logic high/VCC
Trying to set the value of a pin that has not been configured as an output will
produce an 'ERROR' response.
Some pins are reserved for specific functions on Bluefruit modules and can not
be used as GPIO. If you try to make use of a reserved pin number an 'ERROR'
response will be generated.
# Set pin 14 HIGH
AT+HWGPIO=14,1
OK
# Set pin 14 LOW
AT+HWGPIO=14,0
OK
# Read the current state of pin 14
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AT+HWGPIO=14
0
OK
# Try to update a pin that is not set as an output
AT+HWGPIOMODE=14,0
OK
AT+HWGPIO=14,1
ERROR
AT+HWGPIOMODE
This will set the mode for the specified GPIO pin (input, output, etc.).
Codebase Revision: 0.3.0
Parameters: This command one or two values (comma-separated in the case of two
parameters being used):
• The pin number
• The new GPIO mode, where:
◦ 0 = Input
◦ 1 = Output
◦ 2 = Input with pullup enabled
◦ 3 = Input with pulldown enabled
Output: If a single parameters is passed (the GPIO pin number) the current pin mode
will be returned.
Some pins are reserved for specific functions on Bluefruit modules and can not
be used as GPIO. If you try to make use of a reserved pin number an 'ERROR'
response will be generated.
# Configure pin 14 as an output
AT+HWGPIOMODE=14,0
OK
# Get the current mode for pin 14
AT+HWPGIOMODE=14
0
OK
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AT+HWI2CSCAN
Scans the I2C bus to try to detect any connected I2C devices, and returns the
address of devices that were found during the scan process.
Codebase Revision: 0.3.0
Parameters: None
Output: A comma-separated list of any I2C address that were found while scanning
the valid address range on the I2C bus, or nothing is no devices were found.
# I2C scan with two devices detected
AT+HWI2CSCAN
0x23,0x35
OK
# I2C scan with no devices detected
AT+HWI2CSCAN
OK
AT+HWVBAT
Returns the main power supply voltage level in millivolts
Codebase Revision: 0.3.0
Parameters: None
Output: The VBAT level in millivolts
AT+HWVBAT
3248
OK
AT+HWRANDOM
Generates a random 32-bit number using the HW random number generator on the
nRF51822 (based on white noise).
Codebase Revision: 0.4.7
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Parameters: None
Output: A random 32-bit hexadecimal value (ex. '0x12345678')
AT+HWRANDOM
0x769ED823
OK
AT+HWMODELED
Allows you to override the default behaviour of the MODE led (which indicates the
operating mode by default).
Codebase Revision: 0.6.6
Parameters: LED operating mode, which can be one of the following values:
• disable or DISABLE or 0 - Disable the MODE LED entirely to save power
• mode or MODE or 1 - Default behaviour, indicates the current operating mode
• hwuart or HWUART or 2 - Toggles the LED on any activity on the HW UART bus
(TX or RX)
• bleuart or BLEUART or 3 - Toggles the LED on any activity on the BLE UART
Service (TX or RX characteristic)
• spi or SPI or 4 - Toggles the LED on any SPI activity
• manual or MANUAL or 5 - Manually sets the state of the MODE LED via a second
comma-separated parameter, which can be on, off, or toggle.
Output: If run with no parameters, returns an upper-case string representing the
current MODE LED operating mode from the fields above
# Get the curent MODE LED setting
AT+HWMODELED
MODE
OK
# Change the MODE LED to indicate BLE UART activity
AT+HWMODELED=BLEUART
OK
# Manually toggle the MODE LED
AT+HWMODELED=MANUAL,TOGGLE
OK
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AT+UARTFLOW
Enables or disable hardware flow control (CTS + RTS) on the UART peripheral block of
the nRF51822.
Codebase Revision: 0.7.0
Parameters: HW flow control state, which can be one of:
• on
• off
•0
•1
Output: If run with no parameters, returns a number representing whether flow control
is enabled (1) or disabled (0).
# Check the current flow control state
AT+UARTFLOW
1
OK
# Disable HW flow control
AT+UARTFLOW=off
OK
Beacon
Adafruit's Bluefruit LE modules currently support the following 'Beacon' technologies:
• Beacon (Apple) via AT+BLEBEACON
• UriBeacon (Google) via AT+BLEURIBEACON (deprecated)
• Eddystone (Google) via AT+EDDYSTONE*
Modules can be configured to act as 'Beacons' using the following commands:
AT+BLEBEACON
Codebase Revision: 0.3.0
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Parameters: The following comma-separated parameters are required to enable
beacon mode:
• Bluetooth Manufacturer ID (uint16_t)
• 128-bit UUID
• Major Value (uint16_t)
• Minor Value (uint16_t)
• RSSI @ 1m (int8_t)
Output: None
# Enable Apple iBeacon emulation
# Manufacturer ID = 0x004C
AT+BLEBEACON=0x004C,01-12-23-34-45-56-67-78-89-9A-AB-BC-CD-DE-EFF0,0x0000,0x0000,-59
OK
# Reset to change the advertising data
ATZ
OK
# Enable Nordic Beacon emulation
# Manufacturer ID = 0x0059
AT+BLEBEACON=0x0059,01-12-23-34-45-56-67-78-89-9A-AB-BC-CD-DE-EFF0,0x0000,0x0000,-59
OK
# Reset to change the advertising data
ATZ
OK
AT+BLEBEACON will cause the beacon data to be stored in non-volatile config
memory on the Bluefruit LE module, and these values will be persisted across
system resets and power cycles. To remove or clear the beacon data you need
to enter the 'AT+FACTORYRESET' command in command mode.
Entering Nordic Beacon emulation using the sample code above, you can see the
simulated beacon in Nordic's 'Beacon Config' tool below:
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AT+BLEURIBEACON
Converts the specified URI into a UriBeacon (https://adafru.it/edk) advertising packet,
and configures the module to advertise as a UriBeacon (part of Google's Physical
Web (https://adafru.it/ehZ) project).
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To view the UriBeacon URIs you can use one of the following mobile applications:
• Android 4.3+: Physical Web (https://adafru.it/edi) on the Google Play Store
• iOS: Physical Web (https://adafru.it/edj) in Apple's App Store
Codebase Revision: 0.4.7
Parameters: The URI to encode (ex. http://www.adafruit.com/blog (https://adafru.it/ei0))
Output: None of a valid URI was entered (length is acceptable, etc.).
AT+BLEURIBEACON=http://www.adafruit.com/blog
OK
# Reset to change the advertising data
ATZ
OK
If the supplied URI is too long you will get the following output:
AT+BLEURIBEACON=http://www.adafruit.com/this/uri/is/too/long
URL is too long
ERROR
If the URI that you are trying to encode is too long, try using a shortening service
like bit.ly, and encode the shortened URI.
UriBeacon should be considered deprecated as a standard, and EddyStone
should be used for any future development. No further development will happen
in the Bluefruit LE firmware around UriBeacon.
Deprecated: AT+EDDYSTONEENABLE
This command will enable Eddystone (https://adafru.it/fSA) support on the Bluefruit LE
module. Eddystone support must be enabled before the other related commands can
be used.
Codebase Revision: 0.6.6
Parameters: 1 or 0 (1 = enable, 0 = disable)
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Output: The current state of Eddystone support if no parameters are provided (1 =
enabled, 0 = disabled)
This command was removed in firmware 0.7.0 to avoid confusion. Use
AT+EDDYSTONESERVICEEN in 0.7.0 and higher.
# Enable Eddystone support
AT+EDDYSTONEENABLE=1
OK
# Check the current Eddystone status on the module
AT+EDDYSTONEENABLE
1
OK
AT+EDDYSTONEURL
This command will set the URL for the Eddystone-URL (https://adafru.it/fSB) protocol.
Codebase Revision: 0.6.6
Parameters:
• The URL to encode (mandatory)
• An optional second parameter indicates whether to continue advertising the
Eddystone URL even when the peripheral is connected to a central device
• Firmware 0.6.7 added an optional third parameter for the RSSI at 0 meters value.
This should be measured by the end user by checking the RSSI value on the
receiving device at 1m and then adding 41 to that value (to compensate for the
signal strength loss over 1m), so an RSSI of -62 at 1m would mean that you
should enter -21 as the RSSI at 0m. Default value is -18dBm.
Output: Firmware = 0.6.7 running this command with
no parameters will return the current URL.
# Set the Eddystone URL to adafruit
AT+EDDYSTONEURL=http://www.adafruit.com
OK
# Set the Eddystone URL to adafruit and advertise it even when connected
AT+EDDYSTONEURL=http://www.adafruit.com,1
OK
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AT+EDDYSTONECONFIGEN
This command causes the Bluefruit LE module to enable the Eddystone URL config
service for the specified number of seconds.
This command should be used in combination with the Physical Web application from
Google, available for Android (https://adafru.it/edi) or iOS (https://adafru.it/edj). Run
this command then select the 'Edit URL' option from the app to change the destination
URL over the air.
Codebase Revision: 0.6.6
Parameters: The number of seconds to advertised the config service UUID
Output: None
# Start advertising the Eddystone config service for 5 minutes (300s)
AT+EDDYSTONECONFIGEN=300
OK
AT+EDDYSTONESERVICEEN
Adds or removes the Eddystone service from the GATT table (requires a reset to take
effect).
Codebase Revision: 0.7.0
Parameters: Whether or not the Eddystone service should be enabled or not, using on
of the following values:
• on
• off
•1
•0
Output: If the command is executed with no parameters it will disable a numeric value
indicating whether the service is enabled (1) or disabled (0).
You must perform a system reset for this command to take effect.
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# Enable Eddystone service
AT+EddyStonServiceEn=on
OK
AT+EddyStonServiceEn=1
OK
# Disable Eddystone service
AT+EddyStonServiceEn=off
OK
AT+EddyStonServiceEn=0
OK
AT+EDDYSTONEBROADCAST
This command can be used to start of stop advertising the Eddystone payload using
the URL stored in non-volatile memory (NVM).
Codebase Revision: 0.7.0
Parameters: Whether or not the payload should be broadcast, using one of the
following values:
• on
• off
•1
•0
Output: If executed with no parameters, the current broadcast state will be displayed
as a numeric value.
# Enable broadcasting current setting of EddyStone (stored previously on nvm)
AT+EddyStoneBroadcast=on
OK
AT+EddyStoneBroadcast=1
OK
# Disable broadcasting current setting of EddyStone (still stored on nvm)
AT+EddyStoneBroadcast=off
OK
AT+EddyStoneBroadcast=0
OK
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BLE Generic
The following general purpose BLE commands are available on Bluefruit LE modules:
AT+BLEPOWERLEVEL
Gets or sets the current transmit power level for the module's radio (higher transmit
power equals better range, lower transmit power equals better battery life).
Codebase Revision: 0.3.0
Parameters: The TX power level (in dBm), which can be one of the following values
(from lowest to higher transmit power):
• -40
• -20
• -16
• -12
• -8
• -4
•0
•4
Output: The current transmit power level (in dBm)
The updated power level will take effect as soon as the command is entered. If
the device isn't connected to another device, advertising will stop momentarily
and then restart once the new power level has taken effect.
# Get the current TX power level (in dBm)
AT+BLEPOWERLEVEL
0
OK
# Set the TX power level to 4dBm (maximum value)
AT+BLEPOWERLEVEL=4
OK
# Set the TX power level to -12dBm (better battery life)
AT+BLEPOWERLEVEL=-12
OK
# Set the TX power level to an invalid value
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AT+BLEPOWERLEVEL=-3
ERROR
AT+BLEGETADDRTYPE
Gets the address type (for the 48-bit BLE device address).
Normally this will be '1' (random), which means that the module uses a 48-bit address
that was randomly generated during the manufacturing process and written to the die
by the manufacturer.
Random does not mean that the device address is randomly generated every time,
only that a one-time random number is used.
Codebase Revision: 0.3.0
Parameters: None
Output: The address type, which can be one of the following values:
• 0 = public
• 1 = random
AT+BLEGETADDRTYPE
1
OK
AT+BLEGETADDR
Gets the 48-bit BLE device address.
Codebase Revision: 0.3.0
Parameters: None
Output: The 48-bit BLE device address in the following format: 'AA:BB:CC:DD:EE:FF'
AT+BLEGETADDR
E4:C6:C7:31:95:11
OK
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AT+BLEGETPEERADDR
Gets the 48-bit address of the peer (central) device we are connected to.
Codebase Revision: 0.6.5
Parameters: None
Output: The 48-bit address of the connected central device in hex format. The
command will return ERROR if we are not connected to a central device.
Please note that the address returned by the central device is almost always a
random value that will change over time, and this value should generally not be
trusted. This command is provided for certain edge cases, but is not useful in
most day to day scenarios.
AT+BLEGETPEERADDR
48:B2:26:E6:C1:1D
OK
AT+BLEGETRSSI
Gets the RSSI value (Received Signal Strength Indicator), which can be used to
estimate the reliability of data transmission between two devices (the lower the
number the better).
Codebase Revision: 0.3.0
Parameters: None
Output: The RSSI level (in dBm) if we are connected to a device, otherwise '0'
# Connected to an external device
AT+BLEGETRSSI
-46
OK
# Not connected to an external device
AT+BLEGETRSSI
0
OK
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BLE Services
The following commands allow you to interact with various GATT services present on
Bluefruit LE modules when running in Command Mode.
AT+BLEUARTTX
This command will transmit the specified text message out via the UART Service (http
s://adafru.it/iCn) while you are running in Command Mode.
Codebase Revision: 0.3.0
Parameters: The message payload to transmit. The payload can be up to 240
characters (since AT command strings are limited to a maximum of 256 bytes total).
Output: This command will produce an ERROR message if you are not connected to a
central device, or if the internal TX FIFO on the Bluefruit LE module is full.
As of firmware release 0.6.2 and higher, AT+BLEUARTTX can accept a limited set
of escape code sequences:
• \r = carriage return
• \n = new line
• \t = tab
• \b = backspace
• \\ = backward slash
As of firmware release 0.6.7 and higher, AT+BLEUARTTX can accept the following
escape code sequence since AT+BLEUARTTX=? has a specific meaning to the AT
parser:
• \? = transmits a single question mark
As of firmware release 0.7.6 and higher, AT+BLEUARTTX can accept the following
escape code sequence:
• \+ = transmit a single '+' character without having to worry about `+++` mode
switch combinations
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ESCAPE SEQUENCE NOTE: If you are trying to send escape sequences in code
via something like 'ble.print("...");' please note that you will need to send a double
back-slash for the escape code to arrive as-intended in the AT command. For
example: ble.println("AT+BLEUARTTX=Some Test\\r\\n");
You must be connected to another device for this command to execute
# Send a string when connected to another device
AT+BLEUARTTX=THIS IS A TEST
OK
# Send a string when not connected
AT+BLEUARTTX=THIS IS A TEST
ERROR
TX FIFO Buffer Handling
Starting with firmware version 0.6.7, when the TX FIFO buffer is full a 200ms blocking
delay will be used to see if any free space becomes available in the FIFO before
returning ERROR. The exact process is detailed in the flow chart below:
Note: The TX FIFO full check will happen for each GATT transaction (of up to 20
bytes of data each), so large data transfers may have multiple 200ms wait states.
You can use the AT+BLEUARTFIFO=TX (https://adafru.it/id3) command to check the
size of the TX FIFO before sending data to ensure that you have enough free space
available in the buffer.
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The TX FIFO has the following size, depending on the firmware version used:
• Firmware =0.6.7: 1024 characters wide
It IS possible with large data transfers that part of the payload can be
transmitted, and the command can still produce an ERROR if the FIFO doesn't
empty in time in the middle of the payload transfer (since data is transmitted in
maximum 20 byte chunks). If you need to ensure reliable data transfer, you
should always check the TX FIFO size before sending data, which you can do
using the AT+BLEUARTFIFO command. If not enough space is available for the
entire payload, add a SW delay until enough space is available. Any single
AT+BLEUARTTX command can fit into the FIFO, but multiple large instances of
this command may cause the FIFO to fill up mid transfer.
AT+BLEUARTTXF
This is a convenience function the serves the same purpose as AT+BLEUARTTX, but
data is immediately sent in a single BLE packet ('F' for force packet). This command
will accept a maximum of 20 characters, which is the limit of what can be send in a
single packet.
Codebase Revision: 0.7.6
Parameters: See AT+BLEUARTTX
Output: See AT+BLEUARTTX
AT+BLEUARTRX
This command will dump the UART service (https://adafru.it/iCn)'s RX buffer to the
display if any data has been received from from the UART service while running in
Command Mode. The data will be removed from the buffer once it is displayed using
this command.
Any characters left in the buffer when switching back to Data Mode will cause the
buffered characters to be displayed as soon as the mode switch is complete (within
the limits of available buffer space, which is 1024 bytes on current black 32KB SRAM
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devices, or 160 bytes for the blue first generation BLEFriend board based on 16KB
SRAM parts).
Codebase Revision: 0.3.0
Parameters: None
Output: The RX buffer's content if any data is available, otherwise nothing.
You can also use the AT+BLEUARTFIFO=RX command to check if any incoming
data is available or not.
# Command results when data is available
AT+BLEUARTRX
Sent from Android
OK
# Command results when no data is available
AT+BLEUARTRX
OK
AT+BLEUARTFIFO
This command will return the free space available in the BLE UART TX and RX FIFOs.
If you are transmitting large chunks of data, you may want to check if you have
enough free space in the TX FIFO before sending, keeping in mind that individual
GATT packets can contain up to 20 user bytes each.
Codebase Revision: 0.6.7
Parameters: Running this command with no parameters will return two commaseparated values indicating the free space in the TX buffer, following by the RX buffer.
To request a specific buffer, you can execute the command with either a "TX" or "RX"
value (For example: "AT+BLEUARTFIFO=TX").
Output: The free space remaining in the TX and RX FIFO buffer if no parameter is
present, otherwise the free space remaining in the specified FIFO buffer.
AT+BLEUARTFIFO
1024,1024
OK
AT+BLEUARTFIFO=TX
1024
OK
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AT+BLEUARTFIFO=RX
1024
OK
AT+BLEKEYBOARDEN
This command will enable GATT over HID (GoH) keyboard support, which allows you
to emulate a keyboard on supported iOS and Android devices. By default HID
keyboard support is disabled, so you need to set BLEKEYBOARDEN to 1 and then
perform a system reset before the keyboard will be enumerated and appear in the
Bluetooth preferences on your phone, where if can be bonded as a BLE keyboard.
Codebase Revision: 0.5.0
Parameters: 1 or 0 (1 = enable, 0 = disable)
Output: None
As of firmware version 0.6.6 this command is now an alias for AT+BLEHIDEN
You must perform a system reset (ATZ) before the changes take effect!
Before you can use your HID over GATT keyboard, you will need to bond your
mobile device with the Bluefruit LE module in the Bluetooth preferences panel.
# Enable BLE keyboard support then reset
AT+BLEKEYBOARDEN=1
OK
ATZ
OK
# Disable BLE keyboard support then reset
AT+BLEKEYBOARDEN=0
OK
ATZ
OK
AT+BLEKEYBOARD
Sends text data over the BLE keyboard interface (if it has previously been enabled via
AT+BLEKEYBOARDEN).
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Any valid alpha-numeric character can be sent, and the following escape sequences
are also supported:
• \r - Carriage Return
• \n - Line Feed
• \b - Backspace
• \t - Tab
• \\ - Backslash
As of version 0.6.7 you can also use the following escape code when sending a single
character ('AT+BLEKEYBOARD=?' has another meaning for the AT parser):
• \? - Question mark
Codebase Revision: 0.5.0
Parameters: The text string (optionally including escape characters) to transmit
Output: None
# Send a URI with a new line ending to execute in Chrome, etc.
AT+BLEKEYBOARD=http://www.adafruit.com\r\n
OK
# Send a single question mark (special use case, 0.6.7+)
AT+BLEKEYBOARD=\?
OK
AT+BLEKEYBOARDCODE
Sends a raw hex sequence of USB HID keycodes to the BLE keyboard interface
including key modifiers and up to six alpha-numeric characters.
This command accepts the following string-encoded byte array payload, matching the
way HID over GATT sends keyboard data:
• Byte 0: Modifier
• Byte 1: Reserved (should always be 00)
• Bytes 2..7: Hexadecimal value(s) corresponding to the HID keys (if no character
is used you can enter '00' or leave trailing characters empty)
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After a keycode sequence is sent with the AT+BLEKEYBOARDCODE command, you
must send a second AT+BLEKEYBOARDCODE command with at least two 00
characters to indicate the keys were released!
Modifier Values
The modifier byte can have one or more of the following bits set:
• Bit 0 (0x01): Left Control
• Bit 1 (0x02): Left Shift
• Bit 2 (0x04): Left Alt
• Bit 3 (0x08): Left Window
• Bit 4 (0x10): Right Control
• Bit 5 (0x20): Right Shift
• Bit 6 (0x40): Right Alt
• Bit 7 (0x80): Right Window
Codebase Revision: 0.5.0
Parameters: A set of hexadecimal values separated by a hyphen ('-'). Note that these
are HID scan code values, not standard ASCII values!
Output: None
HID Keyboard Codes
A list of hexademical-format HID keyboard codes can be found here (https://adafru.it/
cQV) (see section 7), and are listed below for convenience sake:
HID key code values don't correspond to ASCII key codes! For example, 'a' has
an HID keycode value of '04', and there is no keycode for an upper case 'A' since
you use the modifier to set upper case values. For details, google 'usb hid
keyboard scan codes', and see the example below.
0x00Reserved
0x01Keyboard
0x02Keyboard
0x03Keyboard
0x04Keyboard
0x05Keyboard
0x06Keyboard
0x07Keyboard
(no event indicated)
ErrorRollOver
POSTFail
ErrorUndefined
a and A
b and B
c and C
d and D
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0x08Keyboard e and E
0x09Keyboard f and F
0x0AKeyboard g and G
0x0BKeyboard h and H
0x0CKeyboard i and I
0x0DKeyboard j and J
0x0EKeyboard k and K
0x0FKeyboard l and L
0x10Keyboard m and M
0x11Keyboard n and N
0x12Keyboard o and O
0x13Keyboard p and P
0x14Keyboard q and Q
0x15Keyboard r and R
0x16Keyboard s and S
0x17Keyboard t and T
0x18Keyboard u and U
0x19Keyboard v and V
0x1AKeyboard w and W
0x1BKeyboard x and X
0x1CKeyboard y and Y
0x1DKeyboard z and Z
0x1EKeyboard 1 and !
0x1FKeyboard 2 and @
0x20Keyboard 3 and #
0x21Keyboard 4 and $
0x22Keyboard 5 and %
0x23Keyboard 6 and ^
0x24Keyboard 7 and &
0x25Keyboard 8 and *
0x26Keyboard 9 and (
0x27Keyboard 0 and )
0x28Keyboard Return (ENTER)
0x29Keyboard ESCAPE
0x2AKeyboard DELETE (Backspace)
0x2BKeyboard Tab
0x2CKeyboard Spacebar
0x2DKeyboard - and (underscore)
0x2EKeyboard = and +
0x2FKeyboard [ and {
0x30Keyboard ] and }
0x31Keyboard \ and |
0x32Keyboard Non-US # and ~
0x33Keyboard ; and :
0x34Keyboard ' and "
0x35Keyboard Grave Accent and Tilde
0x36Keyboard, and <
0x37Keyboard . and >
0x38Keyboard / and ?
0x39Keyboard Caps Lock
0x3AKeyboard F1
0x3BKeyboard F2
0x3CKeyboard F3
0x3DKeyboard F4
0x3EKeyboard F5
0x3FKeyboard F6
0x40Keyboard F7
0x41Keyboard F8
0x42Keyboard F9
0x43Keyboard F10
0x44Keyboard F11
0x45Keyboard F12
0x46Keyboard PrintScreen
0x47Keyboard Scroll Lock
0x48Keyboard Pause
0x49Keyboard Insert
0x4AKeyboard Home
0x4BKeyboard PageUp
0x4CKeyboard Delete Forward
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0x4DKeyboard End
0x4EKeyboard PageDown
0x4FKeyboard RightArrow
0x50Keyboard LeftArrow
0x51Keyboard DownArrow
0x52Keyboard UpArrow
0x53Keypad Num Lock and Clear
0x54Keypad /
0x55Keypad *
0x56Keypad 0x57Keypad +
0x58Keypad ENTER
0x59Keypad 1 and End
0x5AKeypad 2 and Down Arrow
0x5BKeypad 3 and PageDn
0x5CKeypad 4 and Left Arrow
0x5DKeypad 5
0x5EKeypad 6 and Right Arrow
0x5FKeypad 7 and Home
0x60Keypad 8 and Up Arrow
0x61Keypad 9 and PageUp
0x62Keypad 0 and Insert
0x63Keypad . and Delete
0x64Keyboard Non-US \ and |
0x65Keyboard Application
0x66Keyboard Power
0x67Keypad =
0x68Keyboard F13
0x69Keyboard F14
0x6AKeyboard F15
0x6BKeyboard F16
0x6CKeyboard F17
0x6DKeyboard F18
0x6EKeyboard F19
0x6FKeyboard F20
0x70Keyboard F21
0x71Keyboard F22
0x72Keyboard F23
0x73Keyboard F24
0x74Keyboard Execute
0x75Keyboard Help
0x76Keyboard Menu
0x77Keyboard Select
0x78Keyboard Stop
0x79Keyboard Again
0x7AKeyboard Undo
0x7BKeyboard Cut
0x7CKeyboard Copy
0x7DKeyboard Paste
0x7EKeyboard Find
0x7FKeyboard Mute
0x80Keyboard Volume Up
0x81Keyboard Volume Down
0x82Keyboard Locking Caps Lock
0x83Keyboard Locking Num Lock
0x84Keyboard Locking Scroll Lock
0x85Keypad Comma
0x86Keypad Equal Sign
0x87Keyboard International1
0x88Keyboard International2
0x89Keyboard International3
0x8AKeyboard International4
0x8BKeyboard International5
0x8CKeyboard International6
0x8DKeyboard International7
0x8EKeyboard International8
0x8FKeyboard International9
0x90Keyboard LANG1
0x91Keyboard LANG2
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0x92Keyboard
0x93Keyboard
0x94Keyboard
0x95Keyboard
0x96Keyboard
0x97Keyboard
0x98Keyboard
0x99Keyboard
0x9AKeyboard
0x9BKeyboard
0x9CKeyboard
0x9DKeyboard
0x9EKeyboard
0x9FKeyboard
0xA0Keyboard
0xA1Keyboard
0xA2Keyboard
0xA3Keyboard
0xA4Keyboard
0xE0Keyboard
0xE1Keyboard
0xE2Keyboard
0xE3Keyboard
0xE4Keyboard
0xE5Keyboard
0xE6Keyboard
0xE7Keyboard
LANG3
LANG4
LANG5
LANG6
LANG7
LANG8
LANG9
Alternate Erase
SysReq/Attention
Cancel
Clear
Prior
Return
Separator
Out
Oper
Clear/Again
CrSel/Props
ExSel
LeftControl
LeftShift
LeftAlt
Left GUI
RightControl
RightShift
RightAlt
Right GUI
The following example shows how you can use this command:
# send 'abc' with left shift key (0x02) --> 'ABC'
AT+BLEKEYBOARDCODE=02-00-04-05-06-00-00
OK
# Indicate that the keys were released (mandatory!)
AT+BLEKEYBOARDCODE=00-00
OK
AT+BLEHIDEN
This command will enable GATT over HID (GoH) support, which allows you to emulate
a keyboard, mouse or media controll on supported iOS, Android, OSX and Windows
10 devices. By default HID support is disabled, so you need to set BLEHIDEN to 1 and
then perform a system reset before the HID devices will be enumerated and appear in
on your central device.
Codebase Revision: 0.6.6
Parameters: 1 or 0 (1 = enable, 0 = disable)
Output: None
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You normally need to 'bond' the Bluefruit LE peripheral to use the HID
commands, and the exact bonding process will change from one operating
system to another.
If you have previously bonded to a device and need to clear the bond, you can
run the AT+FACTORYRESET command which will erase all stored bond data on
the Bluefruit LE module.
# Enable GATT over HID support on the Bluefruit LE module
AT+BLEHIDEN=1
OK
# Reset so that the changes take effect
ATZ
OK
AT+BLEHIDMOUSEMOVE
Moves the HID mouse or scroll wheen position the specified number of ticks.
All parameters are signed 8-bit values (-128 to +127). Positive values move to the right
or down, and origin is the top left corner.
Codebase Revision: 0.6.6
Parameters: X Ticks (+/-), Y Ticks (+/-), Scroll Wheel (+/-), Pan Wheel (+/-)
Output: None
# Move the mouse 100 ticks right and 100 ticks down
AT+BLEHIDMOUSEMOVE=100,100
OK
# Scroll down 20 pixels or lines (depending on context)
AT+BLEHIDMOUSEMOVE=,,20,
OK
# Pan (horizontal scroll) to the right (exact behaviour depends on OS)
AT+BLEHIDMOUSEMOVE=0,0,0,100
AT+BLEHIDMOUSEBUTTON
Manipulates the HID mouse buttons via the specific string(s).
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Codebase Revision: 0.6.6
Parameters: Button Mask String [L][R][M][B][F], Action [PRESS][CLICK][DOUBLECLICK]
[HOLD]
• L = Left Button
• R = Right Button
• M = Middle Button
• B = Back Button
• F = Forward Button
• If the second parameter (Action) is "HOLD", an optional third parameter can be
passed specifying how long the button should be held in milliseconds.
Output: None
# Double click the left mouse button
AT+BLEHIDMOUSEBUTTON=L,doubleclick
OK
# Press the left mouse button down, move the mouse, then release L
# This is required to perform 'drag' then stop type operations
AT+BLEHIDMOUSEBUTTON=L
OK
AT+BLEHIDMOUSEMOVE=-100,50
OK
AT+BLEHIDMOUSEBUTTON=0
OK
# Hold the backward mouse button for 200 milliseconds (OS dependent)
AT+BLEHIDMOUSEBUTTON=B,hold,200
OK
AT+BLEHIDCONTROLKEY
Sends HID media control commands for the bonded device (adjust volume, screen
brightness, song selection, etc.).
Codebase Revision: 0.6.6
Parameters: The HID control key to send, followed by an optional delay in ms to hold
the button
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The control key string can be one of the following values:
• System Controls (works on most systems)
◦ BRIGHTNESS+
◦ BRIGHTNESS• Media Controls (works on most systems)
◦ PLAYPAUSE
◦ MEDIANEXT
◦ MEDIAPREVIOUS
◦ MEDIASTOP
• Sound Controls (works on most systems)
◦ VOLUME
◦ MUTE
◦ BASS
◦ TREBLE
◦ BASS_BOOST
◦ VOLUME+
◦ VOLUME◦ BASS+
◦ BASS◦ TREBLE+
◦ TREBLE• Application Launchers (Windows 10 only so far)
◦ EMAILREADER
◦ CALCULATOR
◦ FILEBROWSER
• Browser/File Explorer Controls (Firefox on Windows/Android only)
◦ SEARCH
◦ HOME
◦ BACK
◦ FORWARD
◦ STOP
◦ REFRESH
◦ BOOKMARKS
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You can also send a raw 16-bit hexadecimal value in the '0xABCD' format. A full list of
16-bit 'HID Consumer Control Key Codes' can be found here (https://adafru.it/cQV)(se
e section 12).
Output: Normally none.
If you are not bonded and connected to a central device, this command will
return ERROR. Make sure you are connected and HID support is enabled before
running these commands.
# Toggle the sound on the bonded central device
AT+BLEHIDCONTROLKEY=MUTE
OK
# Hold the VOLUME+ key for 500ms
AT+BLEHIDCONTROLKEY=VOLUME+,500
OK
# Send a raw 16-bit Consumer Key Code (0x006F = Brightness+)
AT+BLEHIDCONTROLKEY=0x006F
OK
AT+BLEHIDGAMEPADEN
Enables HID gamepad support in the HID service. By default the gamepad is disabled
as of version 0.7.6 of the firmware since it causes problems on iOS and OS X and
should only be used on Android and Windows based devices.
Codebase Revision: 0.7.6
Parameters: Whether the gamepad service should be enabled via one of the following
values:
• on
• off
•1
•0
Output: If executed with no parameters, a numeric value will be returned indicating
whether the battery service is enabled (1) or disabled (0).
This command requires a system reset to take effect.
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AT+BLEHIDGAMEPAD
Sends a specific HID gamepad payload out over BLE
Codebase Revision: 0.7.0
Parameters: The following comma-separated parameters are available:
• x: LEFT, RIGHT: If X=-1 then 'LEFT' is pressed, if X=1 then 'RIGHT' is pressed, if
X=0 then neither left nor right are pressed
• y: UP, DOWN: If Y=-1 then 'UP' is pressed, if Y=1 then 'DOWN' is pressed, if Y=0
then neither up nor down are pressed
• buttons: 0x00-0xFF, which is a bit mask for 8 button 0-7
Output: Nothing
HID gamepad is disabled by default as of version 0.7.6, and must first be enabled
via AT+BLEHIDGAMEPADEN=1 before it can be used.
Note: You need to send both 'press' and 'release' events for each button,
otherwise the system will think that the button is still pressed until a release state
is received.
# Press 'RIGHT' and 'Button0' at the same time
AT+BLEHIDGAMEPAD=1,0,0x01
# Press 'UP' and 'Button1' + 'Button0' at the same time
AT+BLEHIDGAMEPAD=0,-1,0x03
AT+BLEMIDIEN
Enables or disables the BLE MIDI service.
Codebase Revision: 0.7.0
Parameters: State, which can be one of:
• on
• off
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•0
•1
Output: If executed with no parameters, it will return the current state of the MIDI
service as an integer indicating if it is enabled (1) or disabled (0).
Note: This command will require a reset to take effect.
# Check the current state of the MIDI service
AT+BLEMIDIEN
1
OK
# Enable the MIDI Service
AT+BLEMIDIEN=1
OK
AT+BLEMIDIRX
Reads an incoming MIDI character array from the buffer.
Codebase Revision: 0.7.0
Parameters: None
Output: The midi event in byte array format
AT+BLEMIDIRX
90-3C-7F
OK
AT+BLEMIDITX
Sends a MIDI event to host.
Codebase Revision: 0.7.0
Parameters: The MIDI event in hex array format, which can be either:
• A series of full MIDI events (up to 4 events)
• Exactly 1 full MIDI event + several running events without status (up to 7)
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Output: None
# Send 1 event (middle C with max velocity)
AT+BLEMIDITX=90-3C-7F
OK
# Send 2 events
AT+BLEMIDITX=90-3C-7F-A0-3C-7F
OK
# Send 1 full event + running event
AT+BLEMIDITX=90-3C-7F-3C-7F
OK
AT+BLEBATTEN
Enables the Battery Service following the definition from the Bluetooth SIG.
Codebase Revision: 0.7.0
Parameters: Whether the battery service should be enabled, via on of the following
values:
• on
• off
•1
•0
Output: If executed with no parameters, a numeric value will be returned indicating
whether the battery service is enabled (1) or disabled (0).
This command requires a system reset to take effect.
# Enable the Battery Service
AT+BLEBATTEN=1
OK
AT+BLEBATTVAL
Sets the current battery level in percentage (0..100) for the Battery Service (if
enabled).
Codebase Revision: 0.7.0
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Parameters: The percentage for the battery in the range of 0..100.
Output: If executed with no parameters, the current battery level stored in the
characteristic.
# Set the battery level to 72%
AT+BLEBATTVAL=72
OK
BLE GAP
GAP (https://adafru.it/iCo), which stands for the Generic Access Profile, governs
advertising and connections with Bluetooth Low Energy devices.
The following commands can be used to configure the GAP settings on the BLE
module.
You can use these commands to modify the advertising data (for ex. the device name
that appears during the advertising process), to retrieve information about the
connection that has been established between two devices, or the disconnect if you
no longer wish to maintain a connection.
AT+GAPCONNECTABLE
This command can be used to prevent the device from being 'connectable'.
Codebase Revision: 0.7.0
Parameters: Whether or not the device should advertise itself as connectable, using
one of the following values:
• yes
• no
•1
•0
Output: The 'connectable' state of the device if no parameter is provided
# Make the device non-connectable (advertising only)
AT+GAPCONNECTABLE=0
OK
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# Check the current connectability status
AT+GAPCONNECTABLE
1
OK
AT+GAPGETCONN
Diplays the current connection status (if we are connected to another BLE device or
not).
Codebase Revision: 0.3.0
Parameters: None
Output: 1 if we are connected, otherwise 0
# Connected
AT+GAPGETCONN
1
OK
# Not connected
AT+GAPGETCONN
0
OK
AT+GAPDISCONNECT
Disconnects to the external device if we are currently connected.
Codebase Revision: 0.3.0
Parameters: None
Output: None
AT+GAPDISCONNECT
OK
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AT+GAPDEVNAME
Gets or sets the device name, which is included in the advertising payload for the
Bluefruit LE module
Codebase Revision: 0.3.0
Parameters:
• None to read the current device name
• The new device name if you want to change the value
Output: The device name if the command is executed in read mode
Updating the device name will persist the new value to non-volatile memory, and
the updated name will be used when the device is reset. To reset the device to
factory settings and clean the config data from memory run the
AT+FACTORYRESET command.
# Read the current device name
AT+GAPDEVNAME
UART
OK
# Update the device name to 'BLEFriend'
AT+GAPDEVNAME=BLEFriend
OK
# Reset to take effect
ATZ
OK
AT+GAPDELBONDS
Deletes and bonding information stored on the Bluefruit LE module.
Codebase Revision: 0.3.0
Parameters: None
Output: None
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AT+GAPDELBONDS
OK
AT+GAPINTERVALS
Gets or sets the various advertising and connection intervals for the Bluefruit LE
module.
Be extremely careful with this command since it can be easy to cause problems
changing the intervals, and depending on the values selected some mobile devices
may no longer recognize the module or refuse to connect to it.
Codebase Revision: 0.3.0
Parameters: If updating the GAP intervals, the following comma-separated values can
be entered:
• Minimum connection interval (in milliseconds)
• Maximum connection interval (in milliseconds)
• Fast Advertising interval (in milliseconds)
• Fast Advertising timeout (in seconds)
• >= 0.7.0: Low power advertising interval (in milliseconds), default = 417.5 ms
To save power, the Bluefruit modules automatically drop to a lower advertising
rate after 'fast advertising timeout' seconds. The default value is 30 seconds
('Fast Advertising Timeout'). The low power advertising interval is hard-coded to
approximately 0.6s in firmware < 0.7.0. Support to control the low power interval
was added in the 0.7.0 firmware release via an optional fifth parameter.
Please note the following min and max limitations for the GAP parameters:
• Absolute minimum connection interval: 10ms
• Absolute maximum connection interval: 4000ms
• Absolute minimum fast advertising interval: 20ms
• Absolute maximum fast advertisting interval: 10240ms
• Absolute minimum low power advertising interval: 20ms
• Absolute maximum low power advertising interval: 10240ms
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If you only wish to update one interval value, leave the other comma-separated
values empty (ex. ',,110,' will only update the third value, advertising interval).
Output: If reading the current GAP interval settings, the following comma-separated
information will be displayed:
• Minimum connection interval (in milliseconds)
• Maximum connection interval (in milliseconds)
• Advertising interval (in milliseconds)
• Advertising timeout (in milliseconds)
Updating the GAP intervals will persist the new values to non-volatile memory,
and the updated values will be used when the device is reset. To reset the
device to factory settings and clean the config data from memory run the
AT+FACTORYRESET command.
# Read the current GAP intervals
AT+GAPINTERVALS
20,100,100,30
# Update all values
AT+GAPINTERVALS=20,200,200,30
OK
# Update only the advertising interval
AT+GAPINTERVALS=,,150,
OK
AT+GAPSTARTADV
Causes the Bluefruit LE module to start transmitting advertising packets if this isn't
already the case (assuming we aren't already connected to an external device).
Codebase Revision: 0.3.0
Parameters: None
Output: None
# Command results when advertising data is not being sent
AT+GAPSTARTADV
OK
# Command results when we are already advertising
AT+GAPSTARTADV
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ERROR
# Command results when we are connected to another device
AT+GAPSTARTADV
ERROR
AT+GAPSTOPADV
Stops advertising packets from being transmitted by the Bluefruit LE module.
Codebase Revision: 0.3.0
Parameters: None
Output: None
AT+GAPSTOPADV
OK
AT+GAPSETADVDATA
Sets the raw advertising data payload to the specified byte array (overriding the
normal advertising data), following the guidelines in the Bluetooth 4.0 or 4.1 Core
Specification (https://adafru.it/ddd).
In particular, Core Specification Supplement (CSS) v4 contains the details on common
advertising data fields like 'Flags' (Part A, Section 1.3) and the various Service UUID
lists (Part A, Section 1.1). A list of all possible GAP Data Types is available on the
Bluetooth SIG's Generic Access Profile (https://adafru.it/cYs) page.
The Advertising Data payload consists of Generic Access Profile (https://adafru.it/cYs)
data that is inserted into the advertising packet in the following format: [U8:LEN]
[U8:Data Type Value] [n:Value]
WARNING: This command requires a degree of knowledge about the low level
details of the Bluetooth 4.0 or 4.1 Core Specification, and should only be used by
expert users. Misuse of this command can easily cause your device to be
undetectable by central devices in radio range.
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WARNING: This command will override the normal advertising payload and may
prevent some services from acting as expected.
To restore the advertising data to the normal default values use the
AT+FACTORYRESET command.
For example, to insert the 'Flags' Data Type (Data Type Value 0x01), and set the value
to 0x06/0b00000110 (BR/EDR Not Supported and LE General Discoverable Mode) we
would use the following byte array:
02-01-06
• 0x02 indicates the number of bytes in the entry
• 0x01 is the 'Data Type Value (https://adafru.it/cYs)' and indicates that this is a 'Fla
g'
• 0x06 (0b00000110) is the Flag value, and asserts the following fields (see Core
Specification 4.0, Volume 3, Part C, 18.1):
◦ LE General Discoverable Mode (i.e. anyone can discover this device)
◦ BR/EDR Not Supported (i.e. this is a Bluetooth Low Energy only device)
If we also want to include two 16-bit service UUIDs in the advertising data (so that
listening devices know that we support these services) we could append the
following data to the byte array:
05-02-0D-18-0A-18
• 0x05 indicates that the number of bytes in the entry (5)
• 0x02 is the 'Data Type Value (https://adafru.it/cYs)' and indicates that this is an 'I
ncomplete List of 16-bit Service Class UUIDs'
• 0x0D 0x18 is the first 16-bit UUID (which translates to 0x180D, corresponding to
the Heart Rate Service (https://adafru.it/ddB)).
• 0x0A 0x18 is another 16-bit UUID (which translates to 0x180A, corresponding to
the Device Information Service (https://adafru.it/ecj)).
Including the service UUIDs is important since some mobile applications will only
work with devices that advertise a specific service UUID in the advertising
packet. This is true for most apps from Nordic Semiconductors, for example.
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Codebase Revision: 0.3.0
Parameters: The raw byte array that should be inserted into the advertising data
section of the advertising packet, being careful to stay within the space limits defined
by the Bluetooth Core Specification.
Response: None
# Advertise as Discoverable and BLE only with 16-bit UUIDs 0x180D and 0x180A
AT+GAPSETADVDATA=02-01-06-05-02-0d-18-0a-18
OK
The results of this command can be seen in the screenshot below, taken from a
sniffer analyzing the advertising packets in Wireshark. The advertising data payload is
higlighted in blue in the raw byte array at the bottom of the image, and the packet
analysis is in the upper section:
BLE GATT
GATT (https://adafru.it/iCp), which standards for the Generic ATTribute Profile, governs
data organization and data exchanges between connected devices. One device (the
peripheral) acts as a GATT Server, which stores data in Attribute records, and the
second device in the connection (the central) acts as a GATT Client, requesting data
from the server whenever necessary.
The following commands can be used to create custom GATT services and
characteristics on the BLEFriend, which are used to store and exchange data.
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Please note that any characteristics that you define here will automatically be saved
to non-volatile FLASH config memory on the device and re-initialised the next time
the device starts.
You need to perform a system reset via 'ATZ' before most of the commands
below will take effect!
GATT Limitations
The commands below have the following limitations due to SRAM and resource
availability, which should be kept in mind when creating or working with customer
GATT services and characteristics.
These values apply to firmware 0.7.0 and higher:
• Maximum number of services: 10
• Maximum number of characteristics: 30
• Maximum buffer size for each characteristic: 32 bytes
• Maximum number of CCCDs: 16
If you want to clear any previous config value, enter the 'AT+FACTORYRESET'
command before working on a new peripheral configuration.
AT+GATTCLEAR
Clears any custom GATT services and characteristics that have been defined on the
device.
Codebase Revision: 0.3.0
Parameters: None
Response: None
AT+GATTCLEAR
OK
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AT+GATTADDSERVICE
Adds a new custom service definition to the device.
Codebase Revision: 0.3.0
Parameters: This command accepts a set of comma-separated key-value pairs that
are used to define the service properties. The following key-value pairs can be used:
• UUID: The 16-bit UUID to use for this service. 16-bit values should be in
hexadecimal format (0x1234).
• UUID128: The 128-bit UUID to use for this service. 128-bit values should be in
the following format: 00-11-22-33-44-55-66-77-88-99-AA-BB-CC-DD-EE-FF
Response: The index value of the service in the custom GATT service lookup table.
(It's important to keep track of these index values to work with the service later.)
Note: Key values are not case-sensitive
Only one UUID type can be entered for the service (either UUID or UUID128)
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a battery service (UUID = 0x180F) to the peripheral
AT+GATTADDSERVICE=UUID=0x180F
1
OK
# Add a battery measurement characteristic (UUID = 0x2A19), notify enabled
AT+GATTADDCHAR=UUID=0x2A19,PROPERTIES=0x10,MIN_LEN=1,VALUE=100
1
OK
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a custom service to the peripheral
AT+GATTADDSERVICE=UUID128=00-11-00-11-44-55-66-77-88-99-AA-BB-CC-DD-EE-FF
1
OK
# Add a custom characteristic to the above service (making sure that there
# is no conflict between the 16-bit UUID and bytes 3+4 of the 128-bit service UUID)
AT+GATTADDCHAR=UUID=0x0002,PROPERTIES=0x02,MIN_LEN=1,VALUE=100
©Adafruit Industries
Page 120 of 161
1
OK
AT+GATTADDCHAR
Adds a custom characteristic to the last service that was added to the peripheral (via
AT+GATTADDSERVICE).
AT+GATTADDCHAR must be run AFTER AT+GATTADDSERVICE, and will add the
new characteristic to the last service definition that was added.
As of version 0.6.6 of the Bluefruit LE firmware you can now use custom 128-bit
UUIDs with this command. See the example at the bottom of this command
description.
Codebase Revision: 0.3.0
Parameters: This command accepts a set of comma-separated key-value pairs that
are used to define the characteristic properties. The following key-value pais can be
used:
• UUID: The 16-bit UUID to use for the characteristic (which will be insert in the
3rd and 4th bytes of the parent services 128-bit UUID). This value should be
entered in hexadecimal format (ex. 'UUID=0x1234'). This value must be unique,
and should not conflict with bytes 3+4 of the parent service's 128-bit UUID.
• PROPERTIES: The 8-bit characteristic properties field, as defined by the
Bluetooth SIG. The following values can be used:
◦ 0x02 - Read
◦ 0x04 - Write Without Response
◦ 0x08 - Write
◦ 0x10 - Notify
◦ 0x20 - Indicate
• MIN_LEN: The minimum size of the values for this characteristic (in bytes, min =
1, max = 20, default = 1)
• MAX_LEN: The maximum size of the values for the characteristic (in bytes, min =
1, max = 20, default = 1)
• VALUE: The initial value to assign to this characteristic (within the limits of
'MIN_LEN' and 'MAX_LEN'). Value can be an integer ("-100", "27"), a hexadecimal
value ("0xABCD"), a byte array ("aa-bb-cc-dd") or a string ("GATT!").
©Adafruit Industries
Page 121 of 161
• >=0.7.0 - DATATYPE: This argument indicates the data type stored in the
characteristic, and is used to help parse data properly. It can be one of the
following values:
◦ AUTO (0, default)
◦ STRING (1)
◦ BYTEARRAY (2)
◦ INTEGER (3)
• >=0.7.0 - DESCRIPTION: Adds the specified string as the characteristic
description entry
• >=0.7.0 - PRESENTATION: Adds the specified value as the characteristic
presentation format entry
Response: The index value of the characteristic in the custom GATT characteristic
lookup table. (It's important to keep track of these characteristic index values to work
with the characteristic later.)
Note: Key values are not case-sensitive
Make sure that the 16-bit UUID is unique and does not conflict with bytes 3+4 of
the 128-bit service UUID
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a battery service (UUID = 0x180F) to the peripheral
AT+GATTADDSERVICE=UUID=0x180F
1
OK
# Add a battery measurement characteristic (UUID = 0x2A19), notify enabled
AT+GATTADDCHAR=UUID=0x2A19,PROPERTIES=0x10,MIN_LEN=1,VALUE=100
1
OK
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a custom service to the peripheral
AT+GATTADDSERVICE=UUID128=00-11-00-11-44-55-66-77-88-99-AA-BB-CC-DD-EE-FF
1
OK
# Add a custom characteristic to the above service (making sure that there
# is no conflict between the 16-bit UUID and bytes 3+4 of the 128-bit service UUID)
AT+GATTADDCHAR=UUID=0x0002,PROPERTIES=0x02,MIN_LEN=1,VALUE=100
1
OK
©Adafruit Industries
Page 122 of 161
Version 0.6.6 of the Bluefruit LE firmware added the ability to use a new 'UUID128'
flag to add custom 128-bit UUIDs that aren't related to the parent service UUID (which
is used when passing the 16-bit 'UUID' flag).
To specify a 128-bit UUID for your customer characteristic, enter a value resembling
the following syntax:
# Add a custom characteristic to the above service using a
# custom 128-bit UUID
AT+GATTADDCHAR=UUID128=00-11-22-33-44-55-66-77-88-99-AA-BB-CC-DD-EEFF,PROPERTIES=0x02,MIN_LEN=1,VALUE=100
1
OK
Version 0.7.0 of the Bluefruit LE firmware added the new DESCRIPTION and PRESENT
ATION keywoards, corresponding the the GATT Characteristic User Description (https:
//adafru.it/oIA) and the GATT Characteristic Presentation Format (https://adafru.it/oIB)
Descriptors.
The DESCRIPTION field is a string that contains a short text description of the
characteristic. Some apps may not display this data, but it should be visible using
something like the Master Control Panel application from Nordic on iOS and Android.
The PRESENTATION field contains a 7-byte payload that encapsulates the
characteristic presentation format data. It requires a specific set of bytes and values
to work properly. See the following link for details on how to format the payload: https
://developer.bluetooth.org/gatt/descriptors/Pages/DescriptorViewer.aspx?
u=org.bluetooth.descriptor.gatt.characteristic_presentation_format.xml (https://
adafru.it/oIB)
The following example shows how you might use both of these new fields:
AT+GATTADDCHAR=UUID=0x2A37, PROPERTIES=0x10, MIN_LEN=2, MAX_LEN=3, VALUE=00-40,
DESCRIPTION=HRM Measurement, PRESENTATION=17-00-AC-27-01-00-00
For the Characteristic Presentation Format we have:
• Format = IEEE-11073 32-bit FLOAT (Decimal 23, Hex 0x17)
• Exponent = 0/None
• Unit = Thermodynamic temperature: Degrees Fahrenheit (0x27AC) - Bluetooth
LE Unit List (https://adafru.it/oID)
• Namespace = Bluetooth SIG Assigned Number (0x01)
• Description = None (0x0000)
©Adafruit Industries
Page 123 of 161
The results from Nordic's Master Control Panel app can be seen below:
AT+GATTCHAR
Gets or sets the value of the specified custom GATT characteristic (based on the
index ID returned when the characteristic was added to the system via
AT+GATTADDCHAR).
Codebase Revision: 0.3.0
Parameters: This function takes one or two comma-separated functions (one
parameter = read, two parameters = write).
• The first parameter is the characteristic index value, as returned from the
AT+GATTADDCHAR function. This parameter is always required, and if no
second parameter is entered the current value of this characteristic will be
returned.
• The second (optional) parameter is the new value to assign to this characteristic
(within the MIN_SIZE and MAX_SIZE limits defined when creating it).
Response: If the command is used in read mode (only the characteristic index is
provided as a value), the response will display the current value of the characteristics.
If the command is used in write mode (two comma-separated values are provided),
the characteristics will be updated to use the provided value.
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a battery service (UUID = 0x180F) to the peripheral
AT+GATTADDSERVICE=UUID=0x180F
1
OK
©Adafruit Industries
Page 124 of 161
# Add a battery measurement characteristic (UUID = 0x2A19), notify enabled
AT+GATTADDCHAR=UUID=0x2A19,PROPERTIES=0x10,MIN_LEN=1,VALUE=100
1
OK
# Read the battery measurement characteristic (index ID = 1)
AT+GATTCHAR=1
0x64
OK
# Update the battery measurement characteristic to 32 (hex 0x20)
AT+GATTCHAR=1,32
OK
# Verify the previous write attempt
AT+GATTCHAR=1
0x20
OK
AT+GATTLIST
Lists all custom GATT services and characteristics that have been defined on the
device.
Codebase Revision: 0.3.0
Parameters: None
Response: A list of all custom services and characteristics defined on the device.
# Clear any previous custom services/characteristics
AT+GATTCLEAR
OK
# Add a battery service (UUID = 0x180F) to the peripheral
AT+GATTADDSERVICE=UUID=0x180F
1
OK
# Add a battery measurement characteristic (UUID = 0x2A19), notify enabled
AT+GATTADDCHAR=UUID=0x2A19,PROPERTIES=0x10,MIN_LEN=1,VALUE=100
1
OK
# Add a custom service to the peripheral
AT+GATTADDSERVICE=UUID128=00-11-00-11-44-55-66-77-88-99-AA-BB-CC-DD-EE-FF
2
OK
# Add a custom characteristic to the above service (making sure that there
# is no conflict between the 16-bit UUID and bytes 3+4 of the 128-bit service UUID)
AT+GATTADDCHAR=UUID=0x0002,PROPERTIES=0x02,MIN_LEN=1,VALUE=100
2
OK
# Get a list of all custom GATT services and characteristics on the device
AT+GATTLIST
ID=01,UUID=0x180F
ID=01,UUID=0x2A19,PROPERTIES=0x10,MIN_LEN=1,MAX_LEN=1,VALUE=0x64
©Adafruit Industries
Page 125 of 161
ID=02,UUID=0x11, UUID128=00-11-00-11-44-55-66-77-88-99-AA-BB-CC-DD-EE-FF
ID=02,UUID=0x02,PROPERTIES=0x02,MIN_LEN=1,MAX_LEN=1,VALUE=0x64
OK
AT+GATTCHARRAW
This read only command reads binary (instead of ASCII) data from a characteristic. It is
non-printable but has less overhead and is easier when writing libraries in Arduino.
Codebase Revision: 0.7.0
Parameters: The numeric ID of the characteristic to display the data for
Output: Binary data corresponding to the specified characteristic.
Note: This is a specialized command and no NEWLINE is present at the end of
the command!
Debug
The following debug commands are available on Bluefruit LE modules:
Use these commands with care since they can easily lead to a HardFault error on
the ARM core, which will cause the device to stop responding.
AT+DBGMEMRD
Displays the raw memory contents at the specified address.
Codebase Revision: 0.3.0
Parameters: The following comma-separated parameters can be used with this
command:
• The starting address to read memory from (in hexadecimal form, with or without
the leading '0x')
• The word size (can be 1, 2, 4 or 8)
• The number of words to read
©Adafruit Industries
Page 126 of 161
Output: The raw memory contents in hexadecimal format using the specified length
and word size (see examples below for details)
# Read 12 1-byte values starting at 0x10000009
AT+DBGMEMRD=0x10000009,1,12
FF FF FF FF FF FF FF 00 04 00 00 00
OK
# Try to read 2 4-byte values starting at 0x10000000
AT+DBGMEMRD=0x10000000,4,2
55AA55AA 55AA55AA
OK
# Try to read 2 4-byte values starting at 0x10000009
# This will fail because the Cortex M0 can't perform misaligned
# reads, and any non 8-bit values must start on an even address
AT+DBGMEMRD=0x10000009,4,2
MISALIGNED ACCESS
ERROR
AT+DBGNVMRD
Displays the raw contents of the config data section of non-volatile memory
Codebase Revision: 0.3.0
Properties: None
Output: The raw config data from non-volatile memory
AT+DBGNVMRD
FE CA 38 05
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
©Adafruit Industries
03
00
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12
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41
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14
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64
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Page 127 of 161
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AT+DBGSTACKSIZE
Returns the current stack size, to help detect stack overflow or detect stack memory
usage when optimising memory usage on the system.
Codebase Revision: 0.4.7
Parameters: None
Output: The current size of stack memory in bytes
AT+DBGSTACKSIZE
1032
OK
AT+DBGSTACKDUMP
Dumps the current stack contents. Unused sections of stack memory are filled with
'0xCAFEFOOD' to help determine where stack usage stops.
This command is purely for debug and development purposes.
Codebase Revision: 0.4.7
©Adafruit Industries
Page 128 of 161
Parameters: None
Output: The memory contents of the entire stack region
AT+DBGSTACKDUMP
0x20003800: CAFEF00D
0x20003810: CAFEF00D
0x20003820: CAFEF00D
0x20003830: CAFEF00D
0x20003840: CAFEF00D
0x20003850: CAFEF00D
0x20003860: CAFEF00D
0x20003870: CAFEF00D
0x20003880: CAFEF00D
0x20003890: CAFEF00D
0x200038A0: CAFEF00D
0x200038B0: CAFEF00D
0x200038C0: CAFEF00D
0x200038D0: CAFEF00D
0x200038E0: CAFEF00D
0x200038F0: CAFEF00D
0x20003900: CAFEF00D
0x20003910: CAFEF00D
0x20003920: CAFEF00D
0x20003930: CAFEF00D
0x20003940: CAFEF00D
0x20003950: CAFEF00D
0x20003960: CAFEF00D
0x20003970: CAFEF00D
0x20003980: CAFEF00D
0x20003990: CAFEF00D
0x200039A0: CAFEF00D
0x200039B0: CAFEF00D
0x200039C0: CAFEF00D
0x200039D0: CAFEF00D
0x200039E0: CAFEF00D
0x200039F0: CAFEF00D
0x20003A00: CAFEF00D
0x20003A10: CAFEF00D
0x20003A20: CAFEF00D
0x20003A30: CAFEF00D
0x20003A40: CAFEF00D
0x20003A50: CAFEF00D
0x20003A60: CAFEF00D
0x20003A70: CAFEF00D
0x20003A80: CAFEF00D
0x20003A90: CAFEF00D
0x20003AA0: CAFEF00D
0x20003AB0: CAFEF00D
0x20003AC0: CAFEF00D
0x20003AD0: CAFEF00D
0x20003AE0: CAFEF00D
0x20003AF0: CAFEF00D
0x20003B00: CAFEF00D
0x20003B10: CAFEF00D
0x20003B20: CAFEF00D
0x20003B30: CAFEF00D
0x20003B40: CAFEF00D
0x20003B50: CAFEF00D
0x20003B60: CAFEF00D
0x20003B70: CAFEF00D
0x20003B80: CAFEF00D
0x20003B90: CAFEF00D
0x20003BA0: CAFEF00D
0x20003BB0: CAFEF00D
0x20003BC0: CAFEF00D
©Adafruit Industries
CAFEF00D
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Page 129 of 161
0x20003BD0:
0x20003BE0:
0x20003BF0:
0x20003C00:
0x20003C10:
0x20003C20:
0x20003C30:
0x20003C40:
0x20003C50:
0x20003C60:
0x20003C70:
0x20003C80:
0x20003C90:
0x20003CA0:
0x20003CB0:
0x20003CC0:
0x20003CD0:
0x20003CE0:
0x20003CF0:
0x20003D00:
0x20003D10:
0x20003D20:
0x20003D30:
0x20003D40:
0x20003D50:
0x20003D60:
0x20003D70:
0x20003D80:
0x20003D90:
0x20003DA0:
0x20003DB0:
0x20003DC0:
0x20003DD0:
0x20003DE0:
0x20003DF0:
0x20003E00:
0x20003E10:
0x20003E20:
0x20003E30:
0x20003E40:
0x20003E50:
0x20003E60:
0x20003E70:
0x20003E80:
0x20003E90:
0x20003EA0:
0x20003EB0:
0x20003EC0:
0x20003ED0:
0x20003EE0:
0x20003EF0:
0x20003F00:
0x20003F10:
0x20003F20:
0x20003F30:
0x20003F40:
0x20003F50:
0x20003F60:
0x20003F70:
0x20003F80:
0x20003F90:
0x20003FA0:
0x20003FB0:
0x20003FC0:
0x20003FD0:
0x20003FE0:
0x20003FF0:
OK
CAFEF00D
CAFEF00D
CAFEF00D
00000004
CAFEF00D
CAFEF00D
00000001
20001BB0
00000006
20001C6C
20001D38
00000001
00550000
000080E8
60140000
80000000
00000000
200018D4
0000011C
00000000
0000011C
0000011C
00000048
0001E326
000080E8
61C78000
0000A1FC
00000000
000080E8
622C8000
40011000
00000000
62780000
00000000
20003DF8
00000200
00000001
00000001
2000311B
20002050
20002050
20002050
20002050
00000001
00000000
00021263
20003ED8
20003ED4
00000008
FFFFFFFF
20302058
20002050
32002050
20002050
00000000
20003F40
200030D4
000001D8
6C383025
1FFF4000
200020C7
FFFFFFFF
200020B4
200020B0
CAFEF00D
FFFFFFFF
00000000
©Adafruit Industries
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CAFEF00D
CAFEF00D
20001D04
00001098
CAFEF00D
200018D8
000134A5
00000006
20001D44
00000005
00012083
00000001
00000009
20002764
000080E8
0001E4D9
00000000
0001BCE1
0001BC1D
0001BDA9
FFFFFFF9
00000010
00000001
0001E9CF
000080E8
0002125C
0012A236
00000009
0012A29B
000185EF
00000004
00018579
20003054
0002085D
0001F663
2000311B
00000000
00000042
200030D4
20003F1B
0001FFA3
0001FF8B
0012A54E
20002050
00000005
20002050
20003054
20003F64
00000008
2000311B
00000000
32303032
200030D4
20002050
200030D4
20003F60
00016559
00000058
00000028
000166C5
200020B8
000180AD
200020B0
CAFEF00D
FFFFFFFF
00000000
CAFEF00D
CAFEF00D
00000000
CAFEF00D
CAFEF00D
00001006
20001C50
0000100D
20001C38
00000006
20001D38
200018C8
80E80000
60900000
0009608F
00000000
80E80000
80E80000
0000203A
80E80000
80E80000
008B8000
0000A000
80E80000
00000000
00000048
00000000
00000000
00004998
00000042
00006E10
0000000C
2000311B
20002050
00000001
00000001
0001F631
0000000C
200030D4
20002050
20002050
00000005
00000010
00000020
200030D4
0000000C
200030D4
00000000
00000084
00000001
0001F631
0000000C
00323330
20002050
00000020
00000004
000001D6
0000000C
200030D4
00000028
000166AD
2000306C
1FFF4000
1FFF4000
200020B4
1FFF4000
00000000
CAFEF00D
CAFEF00D
CAFEF00D
FFFFEF68
CAFEF00D
200018D8
00000004
20001D28
20001D44
00000005
00000000
000013D3
4FC40000
000080E8
000080E8
00129F5F
200018C8
000000FF
0001BC1D
0001BCE1
0001BDA9
0001BC1D
00000009
51538000
00000009
00000504
000080E8
0001E4D9
000080E8
0001E479
00000000
00000000
0001ACDF
00000001
200030D4
200030D4
00020A6D
200030D4
00020AD7
00020833
0001FF89
20003ED8
00020491
00022409
0001FF8B
20003F74
00020187
20003F75
FFFFFFFF
00000008
00020A6D
200030D4
000258D7
00020833
000001CE
0001ED83
000001D7
00000000
FFFFFFFF
000217F8
00017ED9
200030D4
200020B0
0001A63D
00000002
00000000
00016113
Page 130 of 161
History
This page tracks additions or changes to the AT command set based on the firmware
version number (which you can obtain via the 'ATI' command):
Version 0.7.7
The following AT commands and features were added in the 0.7.7 release:
• Added AT+BLEUARTTXF (F for force) to immediately send the specified data
out in an BLE UART packet (max 20 bytes), bypassing any FIFO delays and
avoiding packets potentially being transmitted in two transactions.
• Adjusted BLE UART service to use min connection interval as the tx interval
• Added AT+DFUIRQ to enable using the DFU Pin for IRQ purposes when there is
a supported event on the nRF51822
• Enabled the internal pullup resistor on the CS pin for Bluefruit SPI boards
• Added AT+MODESWITCHEN to enable/disable +++ mode switching from the
local (serial or SPI) or BLE UART side. By default local = enabled, ble = disabled,
meaning commands can only be executed via the local interface by default.
• Implemented a '\+' escape code to immediately send '+' chars without trigger the
+++ delay waiting for further similar input
• Added AT+BLEHIDGAMEPADEN to separately enable HID Gamepad, since iOS/
OSX has a conflict with gamepad devices causing HID keyboard to not work
properly.
The following bugs were fixed in release 0.7.7:
• Fixed a factory reset issue when a long delay occurs in app_error_handler()
• Fixed an issue where strings were being truncated at 64 chars in UART
• Fixed HID keyboard support not working with iOS 9 & 10
Version 0.7.0
The following AT commands were added in the 0.7.0 release:
• AT+BAUDRATE
Change the HW UART baudrate
©Adafruit Industries
Page 131 of 161
• AT+UARTFLOW
Enable or disable HW UART flow control
• AT+BLEMIDIEN=on/off/0/1
Enable/disable MIDI service, requires a reset to take effect
• AT+BLEMIDITX
Send a MIDI event
• AT+BLEMIDIRX
Receive an available MIDI event
• AT+GATTCHARRAW
Added this read only command to read binary (instead of ASCII) data from a
characteristic. It is non-printable but less overhead and easier for writing library
in Arduino
• AT+NVMWRITE=offset,datatype,data
Writes data to 256 byte user NVM. Datatype must be STRING (1), BYTEARRAY
(2), or INTEGER (3)
• AT+NVMREAD=offset,size,datatype
Reads data back from 256 bytes user NVM
• AT+NVMREADRAW=offset,size binary data
Binary data (instead of ASCII) is returned, ending with "OK\r\n". It is non-printable
but less overhead and easier to use in some situations.
• AT+BLEHIDGAMEPAD=x,y,buttons
◦ X is LEFT, RIGHT: X=-1 LEFT is pressed, X=1 RIGHT is pressed, X=0 no
pressed
◦ Y is UP, DOWN: Y=-1 i UP, Y=1 is DOWN, Y=0 no pressed
◦ Button [0x00-0xFF] is a bit mask for 8 button 0-7
• AT+GAPCONNECTABLE=on/off/1/0
Allow/disallow connection to the device
• AT+EDDYSTONESERVICEEN
Add/remove EddyStone service to GATT table (requires reset)
• AT+EDDYSTONEBROADCAST=on/off/0/1
Start/stop broadcasting url using settings from NVM
• AT+BLEBATTEN=on/off/1/0
Enable battery service. Reset required due to the service change.
• AT+BLEBATTVAL=percent
Updates the Battery level, percent is 0 to 100
©Adafruit Industries
Page 132 of 161
The following commands were changed in the 0.7.0 release:
• AT+GATTADDCHAR
◦ Added a DATATYPE option to indicate the data type for the GATT
characteristic's payload. Valid option are: AUTO (0, default), STRING (1),
BYTEARRAY (2), INTEGER (3)
◦ Added characteristic user description option via the DESCRIPTION flag
◦ Added characteristic presentation format support via the PRESENTATION
flag
• AT+GAPINTERVALS
Added a new 'adv_lowpower_interval' parameter, default value is 417.5 ms.
Current arguments are now: min_conn, max_conn, adv_interval, adv_timeout,
adv_lowpower_interval
Key bug fixes and changes in this release:
• Significant BTLE UART speed and reliability improvements
• Added callback support (work in progress) for:
◦ BLE UART RX
◦ GATT Characteristic(s) RX
◦ MIDI RX
◦ Connect/Disconnect
• Increased MAX_LEN for each characteristic from 20 to 32 bytes
• Changed the default GAP parameters:
◦ Advertising interval = 20ms
◦ Min connection interval = 20 ms
◦ Max connection interval = 40 ms
• Increased the maximum number of CCCDs saved to flash from 8 to 16
• Eddystone config service disabled by default
• Removed AT+EDDYSTONEENABLE to avoid confusion
• Changed advertising timeout for Eddystone to 'unlimited'
• Fixed Write-No-Response characteristic property, which wasn't being handled
properly
• Fixed timing constraints to meet Apple design guidelines
• Fixed systick to ms calculation
• Fixed all tests with google eddystone validator except for writing tx_power = 1
dB (not valid on nrf51)
©Adafruit Industries
Page 133 of 161
• Fixed a bug where writing from the central does not update the value on the
characteristic correctly
• Fixed an issue with HID examples, where when paired with Central, a disconnect
then reconnect could not send HID reports anymore
Version 0.6.7
The following AT commands were added in the 0.6.7 release:
• AT+BLEUARTFIFO
Returns the number of free bytes available in the TX and RX FIFOs for the
Bluetooth UART Service.
The following commands were changed in the 0.6.7 release:
• AT+BLEUARTTX
If the TX FIFO is full, the command will wait up to 200ms to see if the FIFO size
decreases before exiting and returning an ERROR response due to the FIFO
being full.
• AT+BLEURIBEACON
This command will go back to using the old (deprecated) UriBeacon UUID
(0xFED8), and only the AT+EDDYSTONEURL command will use the newer
Eddystone UUID (0xFEAA).
• AT+BLEKEYBOARD and AT+BLEUARTTX
These commands now accept '\?' as an escape code since
'AT+BLEKEYBOARD=?' has another meaning for the AT parser. To send a single
question mark the following command should be used: 'AT+BLEKEYBOARD=\?'
or 'AT+BLEUARTTX=\?'
• AT+EDDYSTONEURL
This command now accepts an optional third parameter for RSSI at 0m value
(default is -18dBm).
Running this command with no parameters ('AT+EDDYSTONEURL\r\n') will now
return the current URL.
Key bug fixes in this release:
• The FIFO handling for the Bluetooth UART Service was improved for speed and
stability, and the TX and RF FIFOs were increased to 1024 bytes each.
©Adafruit Industries
Page 134 of 161
• An issue where a timer overflow was causing factory resets every 4 hours or so
has been resolved.
• Fixed a problem with the GATT server where 'value_len' was being incorrectly
parsed for integer values in characteristics where 'max_len' >4
Version 0.6.6
The following AT commands were added in the 0.6.6 release:
• AT+EDDYSTONEURL
Update the URL for the beacon and switch to beacon mode
• AT+EDDYSTONEENABLE
Enable/disable beacon mode using the configured url
• AT+EDDYSTONECONFIGEN
Enable advertising for the the Eddystone configuration service for the specified
number of seconds
• AT+HWMODELED
Allows the user to override the default MODE LED behaviour with one of the
following options: DISABLE, MODE, HWUART, BLEUART, SPI, MANUAL
• AT+BLECONTROLKEY
Allows HID media control values to be sent to a bonded central device (volume,
screen brightness, etc.)
• AT+BLEHIDEN
Enables or disables BLE HID support in the Bluefruit LE firmware (mouse,
keyboard and media control)
• AT+BLEMOUSEMOVE
To move the HID mouse
• AT+BLEMOUSEBUTTON
To set the state of the HID mouse buttons
The following commands were changed in the 0.6.6 release:
• AT+BLEKEYBOARDEN - Now an alias for AT+BLEHIDEN
• AT+GATTADDCHAR - Added a new UUID128 field to allow custom UUIDs
Key bug fixes in this release:
• Fixed issues with long beacon URLs
• Fixed big endian issue in at+blebeacon for major & minor number
©Adafruit Industries
Page 135 of 161
Known issues with this release:
• Windows 10 seems to support a limited number of characteristics for the DIS
service. We had to disable the Serial Number characteristic to enable HID
support with windows 10.
Version 0.6.5
The following AT commands were added in the 0.6.5 release:
• AT+BLEGETPEERADDR (https://adafru.it/iCq)
The following commands were changed in the 0.6.5 release:
• Increased the UART buffer size (on the nRF51) from 128 to 256 bytes
• +++ now responds with the current operating mode
• Fixed a bug with AT+GATTCHAR values sometimes not being saved to NVM
• Fixed a bug with AT+GATTCHAR max_len value not being taken into account
after a reset (min_len was always used when repopulating the value)
Version 0.6.2
This is the first release targetting 32KB SRAM parts (QFAC). 16KB SRAM parts can't be
used with this firmware due to memory management issues, and should use the
earlier 0.5.0 firmware.
The following AT commands were changed in the 0.6.2 release:
• AT+BLEUARTTX (https://adafru.it/iCr)
Basic escape codes were added for new lines, tabs and backspace
• AT+BLEKEYBOARD (https://adafru.it/iCr)
Also works with OS X now, and may function with other operating systems that
support BLE HID keyboards
©Adafruit Industries
Page 136 of 161
Version 0.5.0
The following AT commands were added in the 0.5.0 release:
• AT+BLEKEYBOARDEN (https://adafru.it/iCr)
• AT+BLEKEYBOARD (https://adafru.it/iCr)
• AT+BLEKEYBOARDCODE (https://adafru.it/iCr)
The following AT commands were changed in the 0.5.0 release:
• ATI (https://adafru.it/iCs)
The SoftDevice, SoftDevice version and bootloader version were added as a
new (7th) record. For Ex: "S110 7.1.0, 0.0" indicates version 7.1.0 of the S110
softdevice is used with the 0.0 bootloader (future boards will use a newer 0.1
bootloader).
Other notes concerning 0.5.0:
Starting with version 0.5.0, you can execute the AT+FACTORYRESET command at any
point (and without a terminal emulator) by holding the DFU button down for 10
seconds until the blue CONNECTED LED starts flashing, then releasing it.
Version 0.4.7
The following AT commands were added in the 0.4.7 release:
• +++ (https://adafru.it/iCs)
• AT+HWRANDOM (https://adafru.it/iCt)
• AT+BLEURIBEACON (https://adafru.it/iCu)
• AT+DBGSTACKSIZE (https://adafru.it/iCv)
• AT+DBGSTACKDUMP (https://adafru.it/iCv)
The following commands were changed in the 0.4.7 release:
• ATI
(https://adafru.it/iCs)The chip revision was added after the chip name. Whereas
©Adafruit Industries
Page 137 of 161
ATI would previously report 'nRF51822', it will now add the specific HW revision
if it can be detected (ex 'nRF51822 QFAAG00')
Version 0.3.0
• First public release
GATT Service Details
Data in Bluetooth Low Energy is organized around units called 'GATT Services (https:/
/adafru.it/iCp)' and 'GATT Characteristics'. To expose data to another device, you
must instantiate at least one service on your device.
Adafruit's Bluefruit LE Pro modules support some 'standard' services, described below
(more may be added in the future).
UART Service
The UART Service is the standard means of sending and receiving data between
connected devices, and simulates a familiar two-line UART interface (one line to
transmit data, another to receive it).
The service is described in detail on the dedicated UART Service (https://adafru.it/iCn)
page.
UART Service
Base UUID: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E
This service simulates a basic UART connection over two lines, TXD and RXD.
It is based on a proprietary UART service specification by Nordic Semiconductors.
Data sent to and from this service can be viewed using the nRFUART apps from
Nordic Semiconductors for Android and iOS.
This service is available on every Bluefruit LE module and is automatically started
during the power-up sequence.
©Adafruit Industries
Page 138 of 161
Characteristics
Nordic’s UART Service includes the following characteristics:
Name
TX
RX
Mandatory
Yes
Yes
UUID
0x0002
0x0003
Type
U8[20]
U8[20]
R
X
W
X
N
I
X
R = Read; W = Write; N = Notify; I = Indicate
Characteristic names are assigned from the point of view of the Central device
TX (0x0002)
This characteristic is used to send data back to the sensor node, and can be written
to by the connected Central device (the mobile phone, tablet, etc.).
RX (0x0003)
This characteristic is used to send data out to the connected Central device. Notify
can be enabled by the connected device so that an alert is raised every time the TX
channel is updated.
Software Resources
To help you get your Bluefruit LE module talking to other Central devices, we've put
together a number of open source tools for most of the major platforms supporting
Bluetooth Low Energy.
Bluefruit LE Client Apps and Libraries
Adafruit has put together the following mobile or desktop apps and libraries to make
it as easy as possible to get your Bluefruit LE module talking to your mobile device or
laptop, with full source available where possible:
©Adafruit Industries
Page 139 of 161
Bluefruit LE Connect (https://adafru.it/f4G) (Android/Java)
Bluetooth Low Energy support was added to Android starting with Android 4.3
(though it was only really stable starting with 4.4), and we've already released Bluefrui
t LE Connect to the Play Store (https://adafru.it/f4G).
The full source code (https://adafru.it/fY9) for Bluefruit LE Connect for Android is also
available on Github to help you get started with your own Android apps. You'll need a
recent version of Android Studio (https://adafru.it/fYa) to use this project.
Bluefruit LE Connect (https://adafru.it/f4H) (iOS/Swift)
Apple was very early to adopt Bluetooth Low Energy, and we also have an iOS
version of the Bluefruit LE Connect (https://adafru.it/f4H) app available in Apple's app
store.
The full swift source code for Bluefruit LE Connect for iOS is also available on Github.
You'll need XCode and access to Apple's developper program to use this project:
• Version 1.x source code: https://github.com/adafruit/Bluefruit_LE_Connect (https:
//adafru.it/ddv)
• Version 2.x source code: https://github.com/adafruit/Bluefruit_LE_Connect_v2 (h
ttps://adafru.it/o9E)
Version 2.x of the app is a complete rewrite that includes iOS, OS X GUI and OS
X command-line tools in a single codebase.
©Adafruit Industries
Page 140 of 161
Bluefruit LE Connect for OS X (https://
adafru.it/o9F) (Swift)
This OS X desktop application is based on the same V2.x codebase as the iOS app,
and gives you access to BLE UART, basic Pin I/O and OTA DFU firmware updates from
the convenience of your laptop or mac.
This is a great choice for logging sensor data locally and exporting it as a CSV, JSON
or XML file for parsing in another application, and uses the native hardware on your
computer so no BLE dongle is required on any recent mac.
The full source is also available on Github (https://adafru.it/o9E).
©Adafruit Industries
Page 141 of 161
Bluefruit LE Command Line Updater for OS
X (https://adafru.it/pLF) (Swift)
This experimental command line tool is unsupported and provided purely as a proof
of concept, but can be used to allow firmware updates for Bluefruit devices from the
command line.
This utility performs automatic firmware updates similar to the way that the GUI
application does, by checking the firmware version on your Bluefruit device (via the
Device Information Service), and comparing this against the firmware versions
available online, downloading files in the background if appropriate.
Simply install the pre-compiled tool via the DMG file (https://adafru.it/pLF) and place it
somewhere in the system path, or run the file locally via './bluefruit' to see the help
menu:
$ ./bluefruit
bluefruit v0.3
Usage:
bluefruit <command> [options...]
Commands:
Scan peripherals:
Automatic update:
Custom firmware:
uuid <uuid>]
Show this screen:
Show version:
scan
update [--enable-beta] [--uuid <uuid>]
dfu --hex <filename> [--init <filename>] [---help
--version
Options:
--uuid <uuid>
If present the peripheral with that uuid is used. If not
present a list of peripherals is displayed
--enable-beta
If not present only stable versions are used
Short syntax:
-u = --uuid, -b = --enable-beta, -h = --hex, -i = --init, -v = --version, -? =
--help
Deprecated: Bluefruit Buddy (https://adafru.it/mCn) (OS X)
This native OS X application is a basic proof of concept app that allows you to
connect to your Bluefruit LE module using most recent macbooks or iMacs. You can
get basic information about the modules and use the UART service to send and
receive data.
The full source for the application is available in the github repo at Adafruit_BluefruitL
E_OSX (https://adafru.it/mCo).
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ABLE (https://adafru.it/ijB) (Cross Platform/Node+Electron)
ABLE (https://adafru.it/ijB) (Adafruit Bluefruit LE Desktop) is a cross-platform desktop
application based on Sandeep Misty's noble library (https://adafru.it/ijC) and the Electr
on (https://adafru.it/ijD) project from Github (used by Atom).
It runs on OS X, Windows 7+ and select flavours of Linux (Ubuntu tested locally).
Windows 7 support is particularly interesting since Windows 7 has no native support
for Bluetooth Low Energy but the noble library talks directly to supported Bluetooth
4.0 USB dongles (http://adafru.it/1327) to emulate BLE on the system (though at this
stage it's still in early BETA and drops the connection and takes more care to work
with).
This app allows you to collect sensor data or perform many of the same functionality
offered by the mobile Bluefruit LE Connect apps, but on the desktop.
The app is still in BETA, but full source (https://adafru.it/ijE) is available in addition to
the easy to use pre-compiled binaries (https://adafru.it/ijB).
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Bluefruit LE Python Wrapper (https://adafru.it/fQF)
As a proof of concept, we've played around a bit with getting Python working with the
native Bluetooth APIs on OS X and the latest version of Bluez on certain Linux targets.
There are currently example sketches showing how to retreive BLE UART data as well
as some basic details from the Device Information Service (DIS).
This isn't an actively support project and was more of an experiment, but if you have a
recent Macbook or a Raspberry Pi and know Python, you might want to look at Adafru
it_Python_BluefruitLE (https://adafru.it/fQF) in our github account.
Debug Tools
If your sense of adventure gets the better of you, and your Bluefruit LE module
goes off into the weeds, the following tools might be useful to get it back from
unknown lands.
These debug tools are provided purely as a convenience for advanced users for
device recovery purposes, and are not recommended unless you're OK with
potentially bricking your board. Use them at your own risk.
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AdaLink (https://adafru.it/fPq) (Python)
This command line tool is a python-based wrapper for programming ARM MCUs using
either a Segger J-Link (https://adafru.it/fYU) or an STLink/V2 (https://adafru.it/ijF). You
can use it to reflash your Bluefruit LE module using the latest firmware from the Bluefr
uit LE firmware repo (https://adafru.it/edX).
Details on how to use the tool are available in the readme.md file on the main Adafruit
_Adalink (https://adafru.it/fPq) repo on Github.
Completely reprogramming a Bluefruit LE module with AdaLink would require four
files, and would look something like this (using a JLink):
adalink nrf51822 --programmer jlink --wipe
--program-hex "Adafruit_BluefruitLE_Firmware/softdevice/
s110_nrf51_8.0.0_softdevice.hex"
--program-hex "Adafruit_BluefruitLE_Firmware/bootloader/bootloader_0002.hex"
--program-hex "Adafruit_BluefruitLE_Firmware/0.6.7/blefriend32/
blefriend32_s110_xxac_0_6_7_150917_blefriend32.hex"
--program-hex "Adafruit_BluefruitLE_Firmware/0.6.7/blefriend32/
blefriend32_s110_xxac_0_6_7_150917_blefriend32_signature.hex"
You can also use the AdaLink tool to get some basic information about your module,
such as which SoftDevice is currently programmed or the IC revision (16KB SRAM or
32KB SRAM) via the --info command:
$ adalink nrf51822 -p jlink --info
Hardware ID : QFACA10 (32KB)
Segger ID
: nRF51822_xxAC
SD Version : S110 8.0.0
Device Addr : **:**:**:**:**:**
Device ID
: ****************
Adafruit nRF51822 Flasher (https://adafru.it/fVL) (Python)
Adafruit's nRF51822 Flasher is an internal Python tool we use in production to flash
boards as they go through the test procedures and off the assembly line, or just
testing against different firmware releases when debugging.
It relies on AdaLink or OpenOCD beneath the surface (see above), but you can use
this command line tool to flash your nRF51822 with a specific SoftDevice, Bootloader
and Bluefruit firmware combination.
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It currently supports using either a Segger J-Link or STLink/V2 via AdaLink, or GPIO
on a Raspberry Pi (https://adafru.it/fVL) if you don't have access to a traditional ARM
SWD debugger. (A pre-built version of OpenOCD for the RPi is included in the repo
since building it from scratch takes a long time on the original RPi.)
We don't provide active support for this tool since it's purely an internal project, but
made it public just in case it might help an adventurous customer debrick a board on
their own.
$ python flash.py --jtag=jlink --board=blefriend32 --softdevice=8.0.0 -bootloader=2 --firmware=0.6.7
jtag
: jlink
softdevice : 8.0.0
bootloader : 2
board
: blefriend32
firmware
: 0.6.7
Writing Softdevice + DFU bootloader + Application to flash memory
adalink -v nrf51822 --programmer jlink --wipe --program-hex
"Adafruit_BluefruitLE_Firmware/softdevice/s110_nrf51_8.0.0_softdevice.hex" -program-hex "Adafruit_BluefruitLE_Firmware/bootloader/bootloader_0002.hex" -program-hex "Adafruit_BluefruitLE_Firmware/0.6.7/blefriend32/
blefriend32_s110_xxac_0_6_7_150917_blefriend32.hex" --program-hex
"Adafruit_BluefruitLE_Firmware/0.6.7/blefriend32/
blefriend32_s110_xxac_0_6_7_150917_blefriend32_signature.hex"
...
BLE FAQ
Can I talk to Classic Bluetooth devices with a Bluefruit LE
modules?
No. Bluetooth Low Energy and 'Classic' Bluetooth are both part of the same
Bluetooth Core Specification -- defined and maintained by the Bluetooth SIG -- but
they are completely different protocols operating with different physical constraints
and requirements. The two protocols can't talk to each other directly.
Can my Bluefruit LE module connect to other Bluefruit LE
peripherals
No, the Bluefruit LE firmware from Adafruit is currently peripheral only, and doesn't
run in Central mode, which would cause the module to behave similar to your
mobile phone or BLE enabled laptop.
If you required Central support, you should look at the newer nRF52832 or
nRF52840 based products like the Adafruit Feather nRF52840 (https://adafru.it/
DLQ) which contains a SoftDevice which is capable of running in either Central or
Peripheral mode. The nRF518322 based products (such as the one used in this
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learning guide) are not capable of running in Central mode because it isn't
supported by the SoftDevice they use, and it isn't possible to update the
SoftDevice safely without special hardware.
I just got my Bluefruit board and when I run a sketch it
hangs forever on the 'Connecting...' stage!
There are several possible explanations here, but the first thing to try is to:
1. Disconnect and close the Bluefruit LE Connect app if it's open
2. Disable BLE on your mobile device
3. Restart your Bluefruit sketch and HW
4. Turn BLE back on again (on the mobile device)
5. Open the Bluefruit LE Connect mobile app again and try to connect again
If problems persist, try performing a Factory Reset of your device (see the
appropriate learning guide for details on how to do this since it varies from one
board to another).
Why are none of my changes persisting when I reset with
the sample sketches?
In order to ensure that the Bluefruit LE modules are in a known state for the
Adafruit demo sketches, most of them perform a factory reset at the start of the
sketch.
This is useful to ensure that the sketch functions properly, but has the side effect of
erasing any custom user data in NVM and setting everything back to factory
defaults every time your board comes out of reset and the sketch runs.
To disable factory reset, open the demo sketch and find
the FACTORYRESET_ENABLE flag and set this to '0', which will prevent the factory
reset from happening at startup.
If you don't see the 'FACTORYRESET_ENABLE' flag in your .ino sketch file, you
probably have an older version of the sketches and may need to update to the
latest version via the Arduino library manager.
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Do I need CTS and RTS on my UART based Bluefruit LE
Module?
Using CTS and RTS isn't strictly necessary when using HW serial, but they should
both be used with SW serial, or any time that a lot of data is being transmitted.
The reason behind the need for CTS and RTS is that the UART block on the
nRF51822 isn't very robust, and early versions of the chip had an extremely small
FIFO meaning that the UART peripheral was quickly overwhelmed.
Using CTS and RTS significantly improves the reliability of the UART connection
since these two pins tell the device on the other end when they need to wait while
the existing buffered data is processed.
To enable CTS and RTS support, go into the BluefruitConfig.h file in your sketch
folder and simply assign an appropriate pin to the macros dedicated to those
functions (they may be set to -1 if they aren't currently being used).
Enabling both of these pins should solve any data reliability issues you are having
with large commands, or when transmitting a number of commands in a row.
How can I update to the latest Bluefruit LE Firmware?
The easiest way to keep your Bluefruit LE modules up to date is with our Bluefruit
LE Connect app for Android (https://adafru.it/f4G) or Bluefruit LE Connect for
iOS (https://adafru.it/f4H). Both of these apps include a firmware update feature
that allows you to automatically download the latest firmware and flash your
Bluefruit LE device in as safe and painless a manner as possible. You can also roll
back to older versions of the Bluefruit LE firmware using these apps if you need to
do some testing on a previous version.
Which firmware version supports 'xxx'?
We regularly release Bluefruit LE firmware images (https://adafru.it/edX) with bug
fixes and new features. Each AT command in this learning guide lists the minimum
firmware version required to use that command, but for a higher level overview of
the changes from one firmware version to the next, consult the firmware history
page (https://adafru.it/iCw).
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Does my Bluefruit LE device support ANCS?
ANCS is on the roadmap for us (most likely in the 0.7.x release family), but we don't
currently support it since there are some unusual edge cases when implementing it
as a service.
My Bluefruit LE device is stuck in DFU mode ... what can I
do?
If your device is stuck in DFU mode for some reason and the firmware was
corrupted, you have several options.
First, try a factory reset by holding down the DFU button for about 10 seconds until
the CONN LED starts flashing, then release the DFU button to perform a factory
reset.
If this doesn't work, you may need to reflash your firmware starting from DFU
mode, which can be done in one of the following ways:
Bluefruit LE Connect (Android)
• Place the module in DFU mode (constant LED blinky)
• Open Bluefruit LE Connect
• Connect to the 'DfuTarg' device
• Once connected, you will see a screen with some basic device information.
Click the '...' in the top-right corner and select Firmware Updates
• Click the Use Custom Firmware button
• Select the appropriate .hex and .init files (copied from the Bluefruit LE
Firmware repo (https://adafru.it/edX)) ... for the BLEFRIEND32 firmware
version 0.6.7, this would be:
◦ Hex File: blefriend32_s110_xxac_0_6_7_150917_blefriend32.hex
◦ Init File: blefriend32_s110_xxac_0_6_7_150917_blefriend32_init.dat
• Click Start Update
Unfortunately, the iOS app doesn't yet support custom firmware updates from DFU
mode yet, but we will get this into the next release.
Nordic nRF Toolbox
You can also use Nordic's nRF Toolbox application to update the firmware using the
OTA bootloader.
On Android:
• Open nRF Toolbox (using the latest version)
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• Click the DFU icon
• Click the Select File button
• Select Application from the radio button list, then click OK
• Find the appropriate .hex file
(ex. 'blefriend32_s110_xxac_0_6_7_150917_blefriend32.hex')
• When asked about the 'Init packet', indicate Yes, and select the appropriate
*_init.dat file (for example:
'blefriend32_s110_xxac_0_6_7_150917_blefriend32_init.dat').
• Click the Select Device button at the bottom of the main screen and find
the DfuTarg device, clicking on it
• Click the Upload button, which should now be enabled on the home screen
• This will begin the DFU update process which should cause the firmware to
be updated or restored on your Bluefruit LE module
On iOS:
• Create a .zip file containing the .hex file and init.dat file that you will use for
the firmware update. For example:
◦ Rename
'blefriend32_s110_xxac_0_6_7_150917_blefriend32.hex' to application.hex
◦ Rename 'blefriend32_s110_xxac_0_6_7_150917_blefriend32_init.dat'
to application.dat
• Upload the .zip file containing the application.hex and application.dat files to
your iPhone using uTunes, as described here (https://adafru.it/iCx)
• Open the nRF Toolbox app (using the latest version)
• Click the DFU icon
• Click the Select File text label
• Switch to User Files to see the .zip file you uploaded above
• Select the .zip file (ex. blefriend32_065.zip)
• On the main screen select Select File Type
• Select application
• On the main screen select SELECT DEVICE
• Select DfuTarg
• Click the Upload button which should now be enabled
• This will begin the DFU process and your Bluefruit LE module will reset when
the update is complete
• If you get the normal 2 or 3 pulse blinky pattern, the update worked!
Adafruit_nRF51822_Flasher
As a last resort, if you have access to a Raspberry Pi, a Segger J-Link or a STLink/
V2, you can also try manually reflashing the entire device, as described in the FAQ
above (https://adafru.it/iCy), with further details on the Software Resources (https://
adafru.it/iCz) page.
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How do I reflash my Bluefruit LE module over SWD?
Reflashing Bluefruit LE modules over SWD (ex. switching to the sniffer firmware and
back) is at your own risk and can lead to a bricked device, and we can't offer any
support for this operation! You're on your own here, and there are
unfortunately 1,000,000 things that can go wrong, which is why we offer two
separate Bluefruit LE Friend boards -- the sniffer and the normal Bluefruit LE Friend
board with the non-sniffer firmware, which provides a bootloader with fail safe
features that prevents you from ever bricking boards via OTA updates.
AdaLink (SWD/JTAG Debugger Wrapper)
Transitioning between the two board types (sniffer and Bluefruit LE module) is
unfortunately not a risk-free operation, and requires external hardware, software
and know-how to get right, which is why it isn't covered by our support team.
That said ... if you're determined to go down that lonely road, and you have a
Segger J-Link (https://adafru.it/fYU) (which is what we use internally for production
and development), or have already erased your Bluefruit LE device, you
should have a look at AdaLink (https://adafru.it/fPq), which is the tool we use
internally to flash the four files required to restore a Bluefruit LE module. (Note:
recent version of AdaLink also support the cheaper STLink/V2 (http://adafru.it/
2548), though the J-Link is generally more robust if you are going to purchase a
debugger for long term use.)
The mandatory Intel Hex files are available in the Bluefruit LE Firmware
repo (https://adafru.it/edX). You will need to flash:
• An appropriate bootloader image
• An appropriate SoftDevice image
• The Bluefruit LE firmware image
• The matching signature file containing a CRC check so that the bootloader
accepts the firmware image above (located in the same folder as the firmware
image)
The appropriate files are generally listed in the version control .xml file (https://
adafru.it/fPr) in the firmware repository.
If you are trying to flash the sniffer firmware (at your own risk!), you only need to
flash a single .hex file, which you can find here (https://adafru.it/fYV). The sniffer
doesn't require a SoftDevice image, and doesn't use the fail-safe bootloader -which is why changing is a one way and risky operation if you don't have a
supported SWD debugger.
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Adafruit_nF51822_Flasher
We also have an internal python tool available that sits one level higher than
AdaLink (referenced above), and makes it easier to flash specific versions of the
official firmware to a Bluefruit LE module. For details, see the
Adafruit_nRF51822_Flasher (https://adafru.it/fVL) repo.
Can I access BETA firmware releases?
The latest versions of the Bluefruit LE Connect applications for iOS and Android
allow you to optionally update your Bluefruit LE modules with pre-release or BETA
firmware.
This functionality is primarilly provided as a debug and testing mechanism for
support issues in the forum, and should only be used when trying to identify and
resolve specific issues with your modules!
Enabling BETA Releases on iOS
• Make sure you have at least version 1.7.1 of Bluefruit LE Connect
• Go to the Settings page
• Scroll to the bottom of the Settings page until you find Bluefruit LE
• Click on the Bluefruit LE icon and enable the Show beta releases switch
• You should be able to see any BETA releases available in the firmware repo
now when you use Bluefruit LE Connect
Enabling BETA Releases on Android
• Make sure you have the latest version of Bluefruit LE Connect
• Open the Bluefruit LE Connect application
• Click the "..." icon in the top-right corner of the app's home screen
• Select Settings
• Scroll down to the Software Updates section and enable Show beta releases
• You should be able to see any BETA releases available in the firmware repo
now when you use Bluefruit LE Connect
Why can't I see my Bluefruit LE device after upgrading to
Android 6.0?
In Android 6.0 there were some important security changes (https://adafru.it/
jcU) that affect Bluetooth Low Energy devices. If location services are unavailable
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(meaning the GPS is turned off) you won't be able to see Bluetooth Low Energy
devices advertising either. See this issue (https://adafru.it/jcV) for details.
Be sure to enable location services on your Android 6.0 device when using
Bluefruit LE Connect or other Bluetooth Low Energy applications with your Bluefruit
LE modules.
What is the theoretical speed limit for BLE?
This depends on a variety of factors, and is determined by the capabilities of the
central device (the mobile phone, etc.) as much as the peripheral.
Taking the HW limits on the nR51822 into account (max 6 packets per connection
interval, and a minimum connection interval of 7.5ms) you end up with the following
theoretical limits on various mobile operating systems:
• iPhone 5/6 + IOS 8.0/8.1
6 packets * 20 bytes * 1/0.030 s = 4 kB/s = 32 kbps
• iPhone 5/6 + IOS 8.2/8.3
3 packets * 20 bytes * 1/0.030 s = 2 kB/s = 16 kbps
• iPhone 5/6 + IOS 8.x with nRF8001
1 packet * 20 bytes * 1/0.030 s = 0.67 kB/s = 5.3 kbps
• Nexus 4
4 packets * 20 bytes * 1/0.0075 s = 10.6 kB/s = 84 kbps
• Nordic Master Emulator Firmware (MEFW) with nRF51822 0.9.0
1 packet * 20 bytes * 1/0.0075 = 2.67 kB/s = 21.33 kbps
• Nordic Master Emulator Firmware (MEFW) with nRF51822 0.11.0
6 packets * 20 bytes * 1/0.0075 = 16 kB/s = 128 kbps
There are also some limits imposed by the Bluefruit LE firmware, but we are
actively working to significantly improve the throughput in the upcoming 0.7.0
release, which will be available Q2 2016. The above figures are useful as a
theoretical maximum to decide if BLE is appropriate for you project or not.
UPDATE: For more specific details on the limitations of various Android versions
and phones, see this helpful post from Nordic Semiconductors (https://adafru.it/
sKc).
Can my Bluefruit board detect other Bluefruit boards or
Central devices?
No. All of our Bluefruit LE modules currently operate in peripheral mode, which
means they can only advertise their own existence via the advertising payload. The
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central device (usually your phone or laptop) is responsible for listening for these
advertising packets, starting the connection process, and inititating any
transactions between the devices. There is no way for a Bluefruit module to detect
other Bluefruit modules or central devices in range, they can only send their own
advertising data out and wait for a connection request to come in.
How can I determine the distance between my Bluefruit
module and my phone in m/ft?
The short answer is: you can't.
RF devices normally measure signal strength using RSSI, which stands for
Received Signal Strength Indicator, which is measured in dBm. The closer the
devices are the strong the RSSI value generally is (-90dBm is much weaker than
-60dBm, for example), but there is no reliable relationship between RSSI values in
dBm and distance in the real world. If there is a wall between devices, RSSI will
fall. If there is a lot of interference on the same 2.4GHz band, RSSI will fall.
Depending on the device, if you simply change the antenna orientation, RSSI will
fall. You can read the RSSI value between two connected devices with
the AT+BLEGETRSSI command, but there are no meaningful and repeatable
conclusions that can be drawn from this value about distance other than perhaps
'farther' or 'closer' in a very loose sense of the terms.
How far away from my phone can I have my Bluefruit LE
module?
This depends on a number of factors beyond the module itself such as antenna
orientation, the antenna design on the phone, transmit power on the sending node,
competing traffic in the same 2.4GHz bandwidth, obstacles between end points,
etc.
It could be as low as a couple meters up to about 10 meters line of sight, but
generally Bluetooth Low Energy is designed for very short range and will work best
in the 5-6 meter or less range for reliable communication, assuming normal
Bluefruit firmware settings.
How many GATT services and characteristics can I
create?
For firmware 0.7.0 and higher, the following limitations are present:
• Maximum number of services: 10
• Maximum number of characteristics: 30
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• Maximum buffer size for each characteristic: 32 bytes
• Maximum number of CCCDs: 16
Is it possible to modify or disable the built in GATT
services and characteristics (DIS, DFU, etc.)?
No, unfortunately you can't. We rely on the Device Information Service (https://
adafru.it/q9E) (DIS) contents to know which firmware and bootloader version you
are running, and wouldn't be able to provide firmware updates without being able
to trust this information, which i why it's both mandatory and read only.
Similarly, the DFU service is mandatory to maintain over the air updates and
disabling it would create more problems that it's presence would cause.
How can I use BlueZ and gatttool with Bluefruit modules?
BlueZ has a bit of a learning curve associated with it, but you can find some notes
below on one option to send and receive data using the BLE UART Service built
into all of our Bluefruit LE modules and boards.
These commands may change with different versions of BlueZ. Version 5.21 was
used below.
# Initialise the USB dongle
$ sudo hciconfig hci0 up
# Scan for the UART BLE device
$ sudo hcitool lescan
D6:4E:06:4F:72:86 UART
# Start gatttool, pointing to the UART device found above
$ sudo gatttool -b D6:4E:06:4F:72:86 -I -t random --sec-level=high
[D6:4E:06:4F:72:86][LE]> connect
Attempting to connect to D6:4E:06:4F:72:86
Connection successful
# Scan for primary GATT Services
[D6:4E:06:4F:72:86][LE]> primary
attr handle: 0x0001, end grp handle:
00001800-0000-1000-8000-00805f9b34fb
attr handle: 0x0008, end grp handle:
00001801-0000-1000-8000-00805f9b34fb
attr handle: 0x0009, end grp handle:
e50e24dcca9e
attr handle: 0x000f, end grp handle:
0000180a-0000-1000-8000-00805f9b34fb
0x0007 uuid:
0x0008 uuid:
0x000e uuid: 6e400001-b5a3-f393-e0a90xffff uuid:
# Get the handles for the entries in the UART service (handle 0x0009)
[D6:4E:06:4F:72:86][LE]> char-desc
handle: 0x0001, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0002, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0003, uuid: 00002a00-0000-1000-8000-00805f9b34fb
handle: 0x0004, uuid: 00002803-0000-1000-8000-00805f9b34fb
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handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
handle:
0x0005,
0x0006,
0x0007,
0x0008,
0x0009,
0x000a,
0x000b,
0x000c,
0x000d,
0x000e,
0x000f,
0x0010,
0x0011,
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
uuid:
00002a01-0000-1000-8000-00805f9b34fb
00002803-0000-1000-8000-00805f9b34fb
00002a04-0000-1000-8000-00805f9b34fb
00002800-0000-1000-8000-00805f9b34fb
00002800-0000-1000-8000-00805f9b34fb
00002803-0000-1000-8000-00805f9b34fb
6e400002-b5a3-f393-e0a9-e50e24dcca9e
00002803-0000-1000-8000-00805f9b34fb
6e400003-b5a3-f393-e0a9-e50e24dcca9e
00002902-0000-1000-8000-00805f9b34fb
00002800-0000-1000-8000-00805f9b34fb
00002803-0000-1000-8000-00805f9b34fb
00002a27-0000-1000-8000-00805f9b34fb
# 6e400002 (handle 0x000b) = TX characteristic
# 6e400003 (handle 0x000d) = RX characteristic
# Optional (but maybe helpful) ... scan for CCCD entries
[D6:4E:06:4F:72:86][LE]> char-read-uuid 2902
handle: 0x000e
value: 00 00
#
#
#
#
#
Enable notifications on the RX characteristic (CCCD handle = 0x000e)
0100 = get notifications
0200 = get indications
0300 = get notifications + indications
0000 = disable notifications + indications
[D6:4E:06:4F:72:86][LE]> char-write-req 0x000e 0100
Characteristic value was written successfully
# Just to make sure it was updated
[D6:4E:06:4F:72:86][LE]> char-read-hnd 0x000e
Characteristic value/descriptor: 01 00
# Writing "test" in the Serial Monitor of the Arduino sketch should
# cause this output not that notifications are enabled:
Notification handle = 0x000d value: 74 65 73 74
# Write something to the TX characteristic (handle = 0x000b)
# This should cause E F G H to appear in the Serial Monitor
[D6:4E:06:4F:72:86][LE]> char-write-cmd 0x000b 45
[D6:4E:06:4F:72:86][LE]> char-write-cmd 0x000b 46
[D6:4E:06:4F:72:86][LE]> char-write-cmd 0x000b 47
[D6:4E:06:4F:72:86][LE]> char-write-cmd 0x000b 48
# To send multiple bytes
[D6:4E:06:4F:72:86][LE]> char-write-cmd 0x000B 707172737475
# If you are running the callbackEcho sketch and notifications
# are enabled you should get this response after the above cmd:
Notification handle = 0x000d value: 70 71 72 73 74 75
-------------# If you just want to enable constant listening, enter the following command from
the CLI:
$ sudo gatttool -b D6:4E:06:4F:72:86 -t random --char-write-req -a 0x000e -n 0100 -listen
# This should give us the following output as data is written on the Uno,
# though we can't send anything back:
Characteristic value was written successfully
Notification handle = 0x000d value: 74 65 73 74
Notification handle = 0x000d value: 6d 6f 72 65 20 74 65 73 74
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Can I use the IRQ pin to wake my MCU up from sleep
when BLE UART data is available?
No, on SPI-based boards the IRQ pin is used to indicate that an SDEP response is
available to an SDEP command. For example, when you sent the `AT+BLEUARTRX`
command as an SDEP message, the Bluefruit firmware running on the nRF51822
will parse the message, prepare an SDEP response, and trigger the IRQ pin to tell
the MCU that the response is ready. This is completely independant from the BLE
UART service, which doesn't have interrupt capability at present.
Can I also update the sketch running on the device using
Bluefruit LE Connect?
No, only the core firmware can be updated over the air. Sketches need to be
loaded using the Arduino IDE and serial bootloader.
Device Recovery
Sometimes, bad things unfortunately happen. Thankfully, 99% of the time it's purely a
SW issue and the Bluefruit devices have a robust bootloader with some fail safes that
can almost always recover your device.
How to Recover a Bluefruit Board
1. Force DFU Mode at Startup
The first step is to force your board into a special bootloader mode, which will
prevent any faulty user sketches or corrupted config data from causing problems.
• Connect the DFU pin to GND with a jumper cable, or if your board has a DFU
button hold the button down when adding power to your board (connecting the
USB cable, etc.)
• Once the device is powered, you should see a faster DFU MODE blinky pattern
that lets you know you are in bootloader mode.
• Now remove the jumper cable between DFU and GND (to prevent going into
DFU mode when you reset)
Remove the jumper cable between DFU and GND once you are in DFU mode so
that you exit it during the next reset!
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2. Update the Bluefruit Firmware
Next, update your device to the latest Bluefruit firmware using the Bluefruit LE
Connect app. We regularly fix bugs, and it's always a good idea to be on the latest
release.
You can perform a firmware update in DFU mode, although the Bluefruit board may
appear as DfuTarg in the Bluefruit LE Connect app, and you will will need to select the
right firmware 'family' for you board.
Because bootloader mode is a fail safe mode and has a small subset of Bluefruit's
features, we can't tell the Bluefruit LE Connect app very many details about our HW.
As such, you will need to indicate which firmware type to flash ... specifically, whether
to flash the UART of SPI based firmware. Be sure to select the right one, based on
your product and the table below:
BLEFRIEND32 Firmware (UART, 32KB SRAM)
• Bluefruit UART Friend V2 (https://adafru.it/edl)
• Bluefruit LE UART Friend (https://adafru.it/tYD)
BLESPIFRIEND Firmware (SPI)
• Bluefruit LE SPI Friend (https://adafru.it/fLp)
• Bluefruit LE Shield (http://adafru.it/2746)
• Bluefruit LE Micro (https://adafru.it/tYE)
• Feather 32u4 Bluefruit LE (https://adafru.it/tYF)
• Feather M0 Bluefruit LE (http://adafru.it/2995)
3. Flash a Test Sketch
Once the core Bluefruit firmware has been updated, flash a test sketch to the device
from the Arduino IDE, such as the following blinky code:
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH);
// turn the LED on (HIGH is the voltage level)
delay(1000);
// wait for a second
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digitalWrite(LED_BUILTIN, LOW);
delay(1000);
// turn the LED off by making the voltage LOW
// wait for a second
}
4. Perform a Factory Reset
Once the core Bluefruit firmware has been updated, the final step is to perform a
factory reset.
• With the board still powered up, connect the DFU pin to GND
• Leave the pin set to GND (or hold the DFU button down) for >5 seconds until the
BLUE status LED starts to blink
• Remove the DFU jumper cable or release the DFU button
This will cause a factory reset which will wipe all config data, and should restore your
board, getting you back to a normal state in most situations!
Still Having Problems?
Hop on over to our support forums (https://adafru.it/dYq) clearly explaining your
problem along with the following information, and, we'll be happy to help:
• You product name and ideally the product ID
• The Bluefruit firmware version you are using (available at the top of the Serial
Monitor output on most example sketches)
• The Operating System your are using
• The Arduino IDE version you are using
Providing the above information in your first post will skip a round of two of back and
forth and you'll get an answer from us quicker, saving everyone time and effort!
Be sure to see the FAQ section of this learning guide as well, which has answer
to many common problems!
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Downloads
Files
• MDBT Datasheet (https://adafru.it/oYE)
• EagleCAD PCB files on GitHub (https://adafru.it/rDV)
• Fritzing object in the Adafruit Fritzing Library (https://adafru.it/aP3)
Schematic
Board Layout
All measurements are in inches.
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