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Adafruit Feather M0 Adalogger Created by lady ada https://learn.adafruit.com/adafruit-feather-m0-adalogger Last updated on 2022-07-27 03:36:48 PM EDT ©Adafruit Industries Page 1 of 57 Table of Contents Overview 5 Pinouts 8 • • • • Power Pins Logic pins Micro SD Card + Green LED Other Pins! Assembly • • • • • • • • • Header Options! Soldering in Plain Headers Prepare the header strip: Add the breakout board: And Solder! Soldering on Female Header Tape In Place Flip & Tack Solder And Solder! Power Management • • • • • 12 22 Battery + USB Power Power Supplies Measuring Battery ENable pin Alternative Power Options Arduino IDE Setup 29 Using with Arduino IDE 31 • • • • • • • • Install SAMD Support Install Adafruit SAMD Install Drivers (Windows 7 & 8 Only) Blink Successful Upload Compilation Issues Manually bootloading Ubuntu & Linux Issue Fix Feather HELP! 39 Using the SD Card 44 • Example logging sketch • Next steps! Adapting Sketches to M0 & M4 • • • • • • 48 Analog References Pin Outputs & Pullups Serial vs SerialUSB AnalogWrite / PWM on Feather/Metro M0 analogWrite() PWM range analogWrite() DAC on A0 ©Adafruit Industries Page 2 of 57 • • • • • • • • • • • • • Missing header files Bootloader Launching Aligned Memory Access Floating Point Conversion How Much RAM Available? Storing data in FLASH Pretty-Printing out registers M4 Performance Options CPU Speed (overclocking) Optimize Cache Max SPI and Max QSPI Enabling the Buck Converter on some M4 Boards Downloads 56 • Datasheets • Schematic • Fabrication Print ©Adafruit Industries Page 3 of 57 ©Adafruit Industries Page 4 of 57 Overview Feather is the new development board from Adafruit, and like it's namesake it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the Adafruit Feather M0 Adalogger - our take on an 'all-in-one' Cortex M0 datalogger (or data-reader) with built in USB and battery charging. Its an Adafruit Feather M0 with a microSD holder ready to rock! We have other boards in the Feather family, check'em out here (https://adafru.it/jAQ) ©Adafruit Industries Page 5 of 57 At the Feather M0's heart is an ATSAMD21G18 ARM Cortex M0 processor, clocked at 48 MHz and at 3.3V logic, the same one used in the new Arduino Zero (http:// adafru.it/2843). This chip has a whopping 256K of FLASH (8x more than the Atmega328 or 32u4) and 32K of RAM (16x as much)! This chip comes with built in USB so it has USB-to-Serial program & debug capability built in with no need for an FTDIlike chip. To make it easy to use for portable projects, we added a connector for any of our 3.7V Lithium polymer batteries and built in battery charging. You don't need a battery, it will run just fine straight from the micro USB connector. But, if you do have a battery, you can take it on the go, then plug in the USB to recharge. The Feather will automatically switch over to USB power when its available. We also tied the battery thru a divider to an analog pin, so you can measure and monitor the battery voltage to detect when you need a recharge. ©Adafruit Industries Page 6 of 57 Here's some handy specs! Like all Feather M0's you get: • Measures 2.0" x 0.9" x 0.28" (51mm x 23mm x 8mm) without headers soldered in • Light as a (large?) feather - 5.3 grams • ATSAMD21G18 @ 48MHz with 3.3V logic/power • 256KB of FLASH + 32KB of RAM • 3.3V regulator with 500mA peak current output • USB native support, comes with USB bootloader and serial port debugging • You also get tons of pins - 20 GPIO pins • Hardware Serial, hardware I2C, hardware SPI support • 8 x PWM pins • 10 x analog inputs • Built in 100mA lipoly charger with charging status indicator LED • Pin #13 red LED for general purpose blinking • Power/enable pin • 4 mounting holes • Reset button The Feather M0 Adalogger uses the extra space left over to add MicroSD + a green LED: • Pin #8 green LED for your blinking pleasure • MicroSD card holder for adding as much storage as you could possibly want, for reading or writing. ©Adafruit Industries Page 7 of 57 Comes fully assembled and tested, with a USB bootloader that lets you quickly use it with the Arduino IDE. We also toss in some header so you can solder it in and plug into a solderless breadboard. Lipoly battery, MicroSD card and USB cable not included (but we do have lots of options in the shop if you'd like!) Check out our tutorial for all sorts of details, including schematics, files, IDE instructions, and more! Pinouts Pretty Pins PDF on GitHub (https://adafru.it/Xlf). ©Adafruit Industries Page 8 of 57 The Feather M0 Adalogger is chock-full of microcontroller goodness. There's also a lot of pins and ports. We'll take you a tour of them now! Power Pins • GND - this is the common ground for all power and logic ©Adafruit Industries Page 9 of 57 • BAT - this is the positive voltage to/from the JST jack for the optional Lipoly battery • USB - this is the positive voltage to/from the micro USB jack if connected • EN - this is the 3.3V regulator's enable pin. It's pulled up, so connect to ground to disable the 3.3V regulator • 3V - this is the output from the 3.3V regulator, it can supply 500mA peak Logic pins This is the general purpose I/O pin set for the microcontroller. All logic is 3.3V Nearly all pins can do PWM output All pins can be interrupt inputs • #0 / RX - GPIO #0, also receive (input) pin for Serial1 (hardware UART), also can be analog input • #1 / TX - GPIO #1, also transmit (output) pin for Serial1, also can be analog input • #20 / SDA - GPIO #20, also the I2C (Wire) data pin. There's no pull up on this pin by default so when using with I2C, you may need a 2.2K-10K pullup. • #21 / SCL - GPIO #21, also the I2C (Wire) clock pin. There's no pull up on this pin by default so when using with I2C, you may need a 2.2K-10K pullup. • #5 - GPIO #5 • #6 - GPIO #6 • #9 - GPIO #9, also analog input A7. This analog input is connected to a voltage divider for the lipoly battery so be aware that this pin naturally 'sits' at around 2VDC due to the resistor divider • #10 - GPIO #10 • #11 - GPIO #11 • #12 - GPIO #12 • #13 - GPIO #13 and is connected to the red LED next to the USB jack • A0 - This pin is analog input A0 but is also an analog output due to having a DAC (digital-to-analog converter). You can set the raw voltage to anything from 0 to 3.3V, unlike PWM outputs this is a true analog output • A1 thru A5 - These are each analog input as well as digital I/O pins. • SCK/MOSI/MISO (GPIO 24/23/22)- These are the hardware SPI pins, you can use them as everyday GPIO pins (but recommend keeping them free as they are best used for hardware SPI connections for high speed. ©Adafruit Industries Page 10 of 57 Micro SD Card + Green LED Since not all pins can be brought out to breakouts, due to the small size of the Feather, we use these to control the SD card! • #4 - used as the MicroSD card CS (chip select) pin • #7 - used as the MicroSD card CD (card detect) pin. If you want to detect when a card is inserted/removed, configure this pin as an input with a pullup. When the pin reads low (0V) then there is no card inserted. When the pin reads high, then a card is in place. It will not tell you if the card is valid, its just a mechanical switch • #8 - This pin was also left over, so we tied it to a green LED, its next to the SD card. It might be handy to blink this LED when writing / reading valid data or some other user-alert! Other Pins! • RST - this is the Reset pin, tie to ground to manually reset the AVR, as well as launch the bootloader manually • ARef - the analog reference pin. Normally the reference voltage is the same as the chip logic voltage (3.3V) but if you need an alternative analog reference, connect it to this pin and select the external AREF in your firmware. Can't go higher than 3.3V! ©Adafruit Industries Page 11 of 57 SWCLK & SWDIO - These pads on the bottom are used to program the chip. They can also be connected to an SWD debugger. Assembly We ship Feathers fully tested but without headers attached - this gives you the most flexibility on choosing how to use and configure your Feather Header Options! Before you go gung-ho on soldering, there's a few options to consider! ©Adafruit Industries Page 12 of 57 The first option is soldering in plain male headers, this lets you plug in the Feather into a solderless breadboard ©Adafruit Industries Page 13 of 57 Another option is to go with socket female headers. This won't let you plug the Feather into a breadboard but it will let you attach featherwings very easily ©Adafruit Industries Page 14 of 57 We also  have 'slim' versions of the female headers, that are a little shorter and give a more compact shape ©Adafruit Industries Page 15 of 57 Finally, there's the "Stacking Header" option. This one is sort of the best-of-bothworlds. You get the ability to plug into a solderless breadboard and plug a featherwing on top. But its a little bulky Soldering in Plain Headers 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 ©Adafruit Industries Page 16 of 57 Add the breakout board: Place the breakout board over the pins so that the short pins poke through the breakout pads And Solder! Be sure to solder all pins for reliable electrical contact. (For tips on soldering, be sure to check out our Guide to Excellent Soldering (https:// adafru.it/aTk)). ©Adafruit Industries Page 17 of 57 Solder the other strip as well. ©Adafruit Industries Page 18 of 57 You're done! Check your solder joints visually and continue onto the next steps Soldering on Female Header Tape In Place For sockets you'll want to tape them in place so when you flip over the board they don't fall out ©Adafruit Industries Page 19 of 57 Flip & Tack Solder After flipping over, solder one or two points on each strip, to 'tack' the header in place ©Adafruit Industries Page 20 of 57 And Solder! Be sure to solder all pins for reliable electrical contact. (For tips on soldering, be sure to check out our Guide to Excellent Soldering (https:// adafru.it/aTk)). ©Adafruit Industries Page 21 of 57 You're done! Check your solder joints visually and continue onto the next steps Power Management ©Adafruit Industries Page 22 of 57 Battery + USB Power We wanted to make our Feather boards easy to power both when connected to a computer as well as via battery. There's two ways to power a Feather: 1. You can connect with a USB cable (just plug into the jack) and the Feather will regulate the 5V USB down to 3.3V. 2. You can also connect a 4.2/3.7V Lithium Polymer (LiPo/LiPoly) or Lithium Ion (LiIon) battery to the JST jack. This will let the Feather run on a rechargeable battery. When the USB power is powered, it will automatically switch over to USB for power, as well as start charging the battery (if attached). This happens 'hot-swap' style so you can always keep the LiPoly connected as a 'backup' power that will only get used when USB power is lost. The JST connector polarity is matched to Adafruit LiPoly batteries. Using wrong polarity batteries can destroy your Feather. The above shows the Micro USB jack (left), LiPoly JST jack (top left), as well as the 3.3V regulator and changeover diode (just to the right of the JST jack) and the LiPoly charging circuitry (to the right of the Reset button). There's also a CHG LED next to the USB jack, which will light up while the battery is charging. This LED might also flicker if the battery is not connected, it's normal. ©Adafruit Industries Page 23 of 57 The charge LED is automatically driven by the LiPoly charger circuit. It will try to detect a battery and is expecting one to be attached. If there isn't one it may flicker once in a while when you use power because it's trying to charge a (nonexistent) battery. It's not harmful, and its totally normal! Power Supplies You have a lot of power supply options here! We bring out the BAT pin, which is tied to the LiPoly JST connector, as well as USB which is the +5V from USB if connected. We also have the 3V pin which has the output from the 3.3V regulator. We use a 500mA peak regulator. While you can get 500mA from it, you can't do it continuously from 5V as it will overheat the regulator. It's fine for, say, powering an ESP8266 WiFi chip or XBee radio though, since the current draw is 'spikey' & sporadic. Measuring Battery If you're running off of a battery, chances are you wanna know what the voltage is at! That way you can tell when the battery needs recharging. LiPoly batteries are 'maxed out' at 4.2V and stick around 3.7V for much of the battery life, then slowly sink down to 3.2V or so before the protection circuitry cuts it off. By measuring the voltage you can quickly tell when you're heading below 3.7V. To make this easy we stuck a double-100K resistor divider on the BAT pin, and connected it to D9 (a.k.a analog #7 A7). You can read this pin's voltage, then double it, to get the battery voltage. ©Adafruit Industries Page 24 of 57 #define VBATPIN A7 float measuredvbat = analogRead(VBATPIN); measuredvbat *= 2; // we divided by 2, so multiply back measuredvbat *= 3.3; // Multiply by 3.3V, our reference voltage measuredvbat /= 1024; // convert to voltage Serial.print("VBat: " ); Serial.println(measuredvbat); This voltage will 'float' at 4.2V when no battery is plugged in, due to the lipoly charger output, so its not a good way to detect if a battery is plugged in or not (there is no simple way to detect if a battery is plugged in) Average Power Draw w/SD Card The average power draw of the ATSAMD21 + regulator circuitry is 11mA. Both the red and green LED each draw 1mA if you light them up. Say you are running this sample sketch which logs the analog voltage on A0 to an SD card file once a second. 1 #include 2 #include 3 4 // Set the pins used 5 #define cardSelect 4 6 7 File logfile; 8 9 10 11 // blink out an error code void error(uint8_t errno) { while(1) { 12 uint8_t i; 13 for (i=0; iBasics->Blink) 4. Select the correct board in the Tools menu, e.g. Feather 32u4, Feather M0, Itsy 32u4 or M0 (physically check your board to make sure you have the right one selected!) 5. Compile it (make sure that works) 6. Click Upload to attempt to upload the code 7. The IDE will print out a bunch of COM Ports as it tries to upload. During this time, double-click the reset button, you'll see the red pulsing LED that tells you its now in bootloading mode 8. The board will show up as the Bootloader COM/Serial port 9. The IDE should see the bootloader COM/Serial port and upload properly ©Adafruit Industries Page 40 of 57 I can't get the Itsy/Feather USB device to show up - I get "USB Device Malfunctioning" errors! This seems to happen when people select the wrong board from the Arduino Boards menu. If you have a Feather 32u4 (look on the board to read what it is you have) Make sure you select Feather 32u4 for ATMega32u4 based boards! Do not use anything else, do not use the 32u4 breakout board line. If you have a Feather M0 (look on the board to read what it is you have) Make sure you select Feather M0 - do not use 32u4 or Arduino Zero If you have a ItsyBitsy M0 (look on the board to read what it is you have) Make sure you select ItsyBitsy M0 - do not use 32u4 or Arduino Zero ©Adafruit Industries Page 41 of 57 I'm having problems with COM ports and my Itsy/Feather 32u4/M0 Theres two COM ports you can have with the 32u4/M0, one is the user port and one is the bootloader port. They are not the same COM port number! When you upload a new user program it will come up with a user com port, particularly if you use Serial in your user program. If you crash your user program, or have a program that halts or otherwise fails, the user COM port can disappear. When the user COM port disappears, Arduino will not be able to automatically start the bootloader and upload new software. So you will need to help it by performing the click-during upload procedure to restart the bootloader, and upload something that is known working like "Blink" I don't understand why the COM port disappears, this does not happen on my Arduino UNO! UNO-type Arduinos have a seperate serial port chip (aka "FTDI chip" or "Prolific PL2303" etc etc) which handles all serial port capability seperately than the main chip. This way if the main chip fails, you can always use the COM port. M0 and 32u4-based Arduinos do not have a seperate chip, instead the main processor performs this task for you. It allows for a lower cost, higher power setup...but requires a little more effort since you will need to 'kick' into the bootloader manually once in a while I'm trying to upload to my 32u4, getting "avrdude: butterfly_recv(): programmer is not responding" errors This is likely because the bootloader is not kicking in and you are accidentally trying to upload to the wrong COM port The best solution is what is detailed above: manually upload Blink or a similar working sketch by hand by manually launching the bootloader ©Adafruit Industries Page 42 of 57 I'm trying to upload to my Feather M0, and I get this error "Connecting to programmer: .avrdude: butterfly_recv(): programmer is not responding" You probably don't have Feather M0 selected in the boards drop-down. Make sure you selected Feather M0. I'm trying to upload to my Feather and i get this error "avrdude: ser_recv(): programmer is not responding" You probably don't have Feather M0 / Feather 32u4 selected in the boards dropdown. Make sure you selected Feather M0 (or Feather 32u4). I attached some wings to my Feather and now I can't read the battery voltage! Make sure your Wing doesn't use pin #9 which is the analog sense for the lipo battery! The yellow LED Is flickering on my Feather, but no battery is plugged in, why is that? The charge LED is automatically driven by the Lipoly charger circuit. It will try to detect a battery and is expecting one to be attached. If there isn't one it may flicker once in a while when you use power because it's trying to charge a (non-existant) battery. It's not harmful, and its totally normal! The Arduino IDE gives me "Device Descriptor Request Failed" This can require "manual bootloading". If you ever get in a 'weird' spot with the bootloader, or you have uploaded code that crashes and doesn't auto-reboot into the bootloader, double-click the RST button to get back into the bootloader. The red LED will pulse, so you know that its in bootloader mode. Do the reset button double-press right as the Arduino IDE says its attempting to upload the sketch, when you see the Yellow Arrow lit and the Uploading ... text in the status bar. ©Adafruit Industries Page 43 of 57  (h ttps://adafru.it/UJA) Don't click the reset button before uploading, unlike other bootloaders you want this one to run at the time Arduino is trying to upload Using the SD Card Once you have your Feather working, you probably want to rock out with some SD card reading and writing! Luckily, the Arduino IDE has an SD card library that works great, and it even comes with the IDE! You can start with CardInfo which is very detailed ©Adafruit Industries Page 44 of 57 Luckily many of the default examples already have chipSelect = 4 For other sketches, do check to make sure that CS is set to 4! The SD card uses hardware SPI for the remaining pins. Make sure you have Adafruit SAMD board package version 1.6.2 or higher, so that Serial debug data goes out on Serial not SerialUSB! One done, upload & open up the serial console and you'll get all this info including a list of files Note that it may not print out the files, thats because the example  root.ls(LS_R | LS_DATE | LS_SIZE) expects to print to Serial rather than SerialUSB. If you want to list the files, use listFiles example Once you have that working, check out the other examples, such the Datalogger example (saving analog data to SD card) and Dumpfile example (reading back data from an SD card) Example logging sketch If you want to try saving data to the SD card in the simplest sketch, try this example. You can adjust the delay() to set how often analog data is read from pin A0 and saved to the SD card. The red LED will blink if there's an error, and the green LED will blink when data is written to the SD card. Note that to save power, we buffer the data, so you will only 'save' data truely every 50 datapoints (512 total characters written) 1 #include 2 #include ©Adafruit Industries Page 45 of 57 3 4 // Set the pins used 5 #define cardSelect 4 6 7 File logfile; 8 9 10 // blink out an error code void error(uint8_t errno) { while(1) { 11 12 uint8_t i; 13 for (i=0; i