TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
Future Technology
Devices
International Ltd
Datasheet
TTL-232R-RPi Debug
Cable for Raspberry Pi
Datasheet
The TTL-232R-RPi cable provides USB to TTL Level UART solutions and
is customised for operation with the Raspberry Pi.
1
Introduction
TTL-232R-RPi is a USB to TTL level serial UART converter cables incorporating FTDI’s FT232RQ USB to
Serial UART interface IC device which handles all the USB signalling and protocols. The TTL-232R-RPi is
designed for use with the Raspberry Pi (RPi), an ultra-low cost, Linux based miniaturised computer. The
debug cable sits on the Rx/Tx of the RPi ARM processor UART – which provides much more detail of
what’s happening within the RPi operating system. Connecting the debug cable to a PC and
communicating with the RPi via a terminal emulator on a PC gives the user access to more detailed
information from the Linux kernel during RPi start-up, which appears on the Rx/TX lines of the UART, as
well as being able to login and access the kernel itself from the PC.
1.1 Features
TTL-232R-RPi Debug cable provides a USB to
TTL Serial interface for Raspberry Pi computer.
5V safe TTL inputs make the TTL-232R easy to
interface to 5V MCU’s.
On board FT232RQ provides single chip USB to
asynchronous serial data transfer interface.
Entire USB protocol handled by the electronics
in the cable USB.
FTDI’s royalty-free VCP allow for communication
as a standard emulated COM port and D2XX
‘direct’ drivers provide DLL application
programming interface.
Connect directly to a microcontroller UART or
I/O pins.
Support for FT232R FTDIChip-ID™ feature for
improved security.
UART interface support for 7 or 8 data bits, 1 or
2 stop bits and odd / even / mark / space / no
parity.
3x ‘flying leads’ outputs provide TXD, RXD and
GND signals.
Low USB bandwidth consumption.
UHCI / OHCI / EHCI host controller compatible.
USB 2.0 Full Speed compatible.
-40°C to +85°C operating temperature range.
Cable length is 1.0m.
FCC and CE compliant.
Fully assisted or X-On / X-Off software
handshaking.
Data transfer rates from 300 baud to 3 Mbaud
at TTL levels.
Internal EEPROM with user writeable area.
Use of FTDI devices in life support and/or safety applications is entirely at the user’s risk, and the user agrees
to defend, indemnify and hold harmless FTDI from any and all damages, claims, suits or expense resulting
from such use.
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
1.2 Ordering Information
Part Number
Description
TTL-232R-RPi
USB to UART, 3.3V TTL logic level, Raspberry Pi compatible flying leads
Table 1-1 – USB-RS232 Adapter Ordering Information
2
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
Table of Contents
1
2
Introduction ................................................................................... 1
1.1
Features ........................................................................................................ 1
1.2
Ordering Information .................................................................................... 2
Driver Support ................................................................................ 4
2.1
Driver Operation Examples ........................................................................... 4
3
Operational Descriptions ................................................................ 5
4
Functional Descriptions .................................................................. 5
4.1
TTL-232R-RPi Wire Configuration ................................................................. 5
4.2
TTL-232R-RPi Debug cable Signal Descriptions ............................................. 6
4.3
TTL-232R-RPi Debug cable Electrical Parameters.......................................... 6
5
TTL-232R-RPi Debug cable connection diagram ............................. 7
6
Advanced Features of the TTL-232R-RPi......................................... 7
7
TTL-232R-RPi Circuit Schematic ..................................................... 8
8
Internal EEROM Configuration ........................................................ 9
9
Contact Information ..................................................................... 10
Appendix A – List of Tables and Figures ................................................................ 10
Appendix B – Revision History .............................................................................. 11
3
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
2
Clearance No.: FTDI# 296
Driver Support
Royalty-Free VIRTUAL COM PORT (VCP)
DRIVERS for:
Royalty-Free D2XX Direct Drivers (USB Drivers +
DLL S/W Interface):
Windows 7 32,64-bit
Windows 7 32,64-bit
Windows Vista
Windows Vista
Windows XP 32,64-bit
Windows XP 32,64-bit
Windows XP Embedded
Windows XP Embedded
Windows CE.NET 4.2 , 5.0 and 6.0
Windows CE.NET 4.2, 5.0 and 6.0
MAC OS OS-X
MAC OS OS-X
Linux 2.6.32 or later
Linux 2.6.32 or later
ARM Linux
ARM Linux
Android
Android
The drivers listed above are all available to download for free from www.ftdichip.com. Various 3rd Party
Drivers are also available for various other operating systems - visit www.ftdichip.com for details.
For driver installation instructions please see:
http://www.ftdichip.com/Support/Documents/InstallGuides.htm.
2.1 Driver Operation Examples
The TTL-232R-RPi debug cables require USB drivers, available free from http://www.ftdichip.com, which
are used to make the FT232R in the cable appear as a virtual COM port (VCP). This then allows the user
to communicate with the USB interface via a standard PC serial emulation port (for example TTY).
Another FTDI USB driver, the D2XX driver, can also be used with application software to directly access
the FT232R on the cable though a DLL. This is illustrated in the Figure 2-1.
TTL-232R-Rpi
Debug Cable
VCP
TTY
3x 0.1" Single Pole Connectors
USB
Virtual COM Port
DLL
D2XX
TTY
3x 0.1" Single Pole Connectors
USB
Software application access to USB via D2XX
Figure 2-1 – Using the TTL-232R-RPi Generic Cable
4
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
Operational Descriptions
3
TTL-232R-RPi is a USB-to-TTL Serial UART debug cable. It is designed to be used with the Raspberry Pi
(RPi) Linux-based computer. This cable provides a fast, simple way for a PC to interface with an RPi, to
carry out program analysis and debugging.
This cable is electrically configured to process and drive +3.3 V logic level UART signals. The USB side of
the cable is USB powered and USB 2.0 Full Speed compatible, supporting data transfer rates up to 3
Mbaud. Spanning 1.0m in length, the TTL-232R-RPi debug cable connects directly to the serial port on
the RPi board. The RPi’s serial port can output kernel debug messages even if it has not been completely
booted.
The following serial communication parameters should be used to access the serial/debugger port on
Raspberry Pi board:
* Speed:
115200 baud
* Bits:
8
* Parity:
None
* Stop Bits:
1
* Flow Control: None
For more information about the Raspberry Pi Computer refer to the Raspberry Pi Foundation web site:
http://www.raspberrypi.org/
Functional Descriptions
4
4.1 TTL-232R-RPi Wire Configuration
The following Figure 4-1 shows the cable signals and the wire colours for these signals on the TTL-232RRPi generic cables.
3x single pole
0.1in pitch header
1
BLACK
CABLE 1.0m
2
ORANGE
4
3
YELLOW
Figure 4-1 – TTL-232R-RPi Debug cable Pin Out
2.60mm
+/-0.05
2.54mm
+/-0.05
14.0mm
+/-0.2
Figure 4-2 – TTL-232R-RPi Debug cable, Single Pole Header Mechanical Details
5
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
4.2 TTL-232R-RPi Debug cable Signal Descriptions
Header Pin
Name
Type
Colour
Description
GND
GND
Black
Device ground supply pin. Connect to ground pin on RPi
Number
1
board
2
TXD
Output
Orange
Transmit Asynchronous Data output. Connect to RXD input
on RPi board
3
RXD
Input
Yellow
Receive Asynchronous Data input. Connect to TXD output
on RPi board
Table 4-1 – TTL-232R-RPi Debug cable Signal Descriptions
4.3 TTL-232R-RPi Debug cable Electrical Parameters
Parameter
VCC
Description
Power Input Voltage
Minimum
Typical
Maximum
Units
4.25
5.0
5.25
V
Conditions
Dependant on the USB
port that the TTL-232RRPi Debug cable is
connected to
IO
Power Input Current
-
-
15
mA
Less than 70uA during
suspend.
T
Operating Temperature
-40
-
+85
o
C
Range
Table 4-2 – TTL-232R-RPi Debug cable Operating Parameters
Parameter
Description
Minimum
Typical
Maximum
Units
Conditions
Voh
Output Voltage High
2.2
2.8
3.2
V
I source = 3mA
Vol
Output Voltage Low
0.3
0.4
0.6
V
I sink = 8mA
Vin
Input Switching Threshold
1.0
1.2
1.5
V
Vhys
Input Switching Hysteresis
20
25
30
mV
Table 4-3 – TTL-232R- RPi Debug cable I/O Pin Characteristics
6
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
5
Clearance No.: FTDI# 296
TTL-232R-RPi Debug cable connection diagram
The TTL-232R-RPi Debug cable should be connected to Raspberry Pi board according to the diagram
below.
Please note that TXD-orange wire should be connected to RX pin on RPi board and RXD-yellow wire
should be connected to TX pin on RPi board.
bottom left
top left
3x single pole
0.1in pitch header
1
GND
0V (GND)
BLACK
TX
CABLE 1.0m
3
2
RX
YELLOW
TX
ORANGE
RX
Figure 5-1 – TTL-232R-RPi Debug cable, connection diagram
6
Advanced Features of the TTL-232R-RPi
The TTL-232R-RPi debug cable utilizes FTDI’s FT232RQ USB to serial IC device. This section summarises
the key features of the FT232RQ which apply to the TTL-232R-RPi debug cables. For further details, and a
full features and enhancements description consult the FT232R datasheet, this is available from
www.ftdichip.com.
Internal EEPROM. The internal EEPROM in each cable is used to store USB Vendor ID (VID), Product ID
(PID), device serial number, product description string and various other USB configuration descriptors.
Each cable is supplied with the internal EEPROM pre-programmed as described
Lower Operating and Suspend Current. The FT232R has a low 15mA operating supply current and a
very low USB suspend current of approximately 70μA.
Low USB Bandwidth Consumption. The USB interface of the FT232R, and therefore the TTL-232R
cables has been designed to use as little as possible of the total USB bandwidth available from the USB
host controller.
High Output Drive Option. The UART interface I/O pins on the TTL-232R-RPi Debug cable (RXD and
TXD) can be configured to use the FT232R’s high output drive option. This option allows the FT232R I/O
pins to drive up to three times the standard signal drive level. This allows multiple devices to be driven,
or devices that require greater signal drive strength to be interfaced to the cables. This option is enabled
in the internal EEPROM.
UART Pin Signal Inversion. The sense of UART signals can be individually inverted by configuring
options in the internal EEPROM. For example RXD (active high) can be changed to RXD# (active low) and
TXD can be changed to TXD#.
FTDIChip-ID™. The FT232R includes the new FTDIChip-ID™ security dongle feature. This FTDIChip-ID™
feature allows a unique number to be burnt into each cable during manufacture. This number cannot be
reprogrammed. An application note, AN232R-02, available from FTDI website (www.ftdichip.com)
describes this feature.
7
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
7
Clearance No.: FTDI# 296
TTL-232R-RPi Circuit Schematic
The circuit schematic for the small internal electronic circuit board, utilising the FTDI FT232R, which is
encapsulated into the USB connector end of the cable, is shown in Figure 7-1.
Customised versions of these cables are also available. Users interested in customised versions of these
cables should contact FTDI sales (sales1@ftdichip.com).
CN-USB
CN1
5
1
2
3
4
C3
47pF
GND
C5
4.7uF
GND
C4
47pF
GND
C2
0.1uF
GND
16
15
14
18
27
3V3OUT
VCC
19
1
TXD
RXD
RTS
CTS
DTR
DSR
DCD
RI
30
2
32
8
31
6
7
3
22
21
10
11
9
FT232RQ
CBUS0
CBUS1
CBUS2
CBUS3
CBUS4
VCCIO
U1
USBDM
USBDP
RESET#
OSCI
OSCO
AGND
GND
GND
GND
GND
VCC
FB1
600R/0.5A
C1
10nF
GND
28
26
TEST
GND
24
4
17
20
33
R1
100R
TXD
RXD
GND
[Orange]
[Yellow]
[Black]
Figure 7-1 – Circuit Schematic of PCB Used in the TTL 232R-RPi Debug cable
8
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
8
Clearance No.: FTDI# 296
Internal EEROM Configuration
The TTL-232R-RPi Debug cable is controlled by the FTDI FT232R IC. This FT232R device contains an
EEPROM which contains the USB configuration descriptors for that device. When the cable is plugged into
a PC or a USB reset is performed, the PC will read these descriptors. The default values stored into the
internal EEPROM are defined in Table 8.1
Parameter
Value
USB Vendor ID (VID)
0403h
USB Product UD (PID)
6001h
Serial Number Enabled?
See Note
Pull down I/O Pins in USB
Disabled
Suspend
Manufacturer Name
FTDI
Product Description
TTL232R-3V3
Power Source
FTDI default VID (hex)
FTDI default PID (hex)
Yes
Serial Number
Max Bus Power Current
Notes
A unique serial number is generated and programmed into the
EEPROM during device final test.
Enabling this option will make the device pull down on the UART
interface lines when the power is shut off (PWREN# is high).
90mA
Bus Powered
Device Type
FT232R
USB Version
0200
Remote Wake Up
Disabled
High Current I/Os
Enabled
Load VCP Driver
Enabled
Invert TXD
Disabled
Invert RXD
Disabled
Invert RTS#
Disabled
Invert CTS#
Disabled
Returns USB 2.0 device description to the host.
Enables the high drive level on the UART and CBUS I/O pins.
Makes the device load the VCP driver interface for the device.
Signal on this pin becomes TXD# if enable.
Signal on this pin becomes RXD# if enable.
Signal on this pin becomes RTS if enable.
Signal on this pin becomes CTS if enable.
Table 8-1 – Default Internal EEPROM Configuration
The internal EEPROM in the cable can be re-programmed over USB using the utility program FT_PROG.
FT_PROG can be downloaded from the www.ftdichip.com.
9
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
9
Clearance No.: FTDI# 296
Contact Information
Head Office – Glasgow, UK
Branch Office – Hillsboro, Oregon, USA
Future Technology Devices International Limited
Unit 1, 2 Seaward Place, Centurion Business Park
Glasgow G41 1HH
United Kingdom
Tel: +44 (0) 141 429 2777
Fax: +44 (0) 141 429 2758
Future Technology Devices International Limited (USA)
7235 NW Evergreen Parkway, Suite 600
Hillsboro, OR 97123-5803
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987
E-mail (Sales)
E-mail (Support)
E-mail (General Enquiries)
E-Mail (Sales)
E-Mail (Support)
E-Mail (General Enquiries)
sales1@ftdichip.com
support1@ftdichip.com
admin1@ftdichip.com
us.sales@ftdichip.com
us.support@ftdichip.com
us.admin@ftdichip.com
Branch Office – Taipei, Taiwan
Branch Office – Shanghai, China
Future Technology Devices International Limited (Taiwan)
2F, No. 516, Sec. 1, NeiHu Road
Taipei 114
Taiwan , R.O.C.
Tel: +886 (0) 2 8791 3570
Fax: +886 (0) 2 8791 3576
Future Technology Devices International Limited (China)
Room 1103, No. 666,
West Huaihai Road,
Shanghai, 200052
China
Tel: +86 21 62351596
Fax: +86 21 62351595
E-mail (Sales)
E-mail (Support)
E-mail (General
Enquiries)
asia.sales1@ftdichip.com
asia.support1@ftdichip.com
asia.admin1@ftdichip.com
E-mail (Sales)
E-mail (Support)
E-mail (General Enquiries)
cn.sales@ftdichip.com
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cn.admin@ftdichip.com
Web Site
http://ftdichip.com
Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) and sales
representative(s) in your country.
System and equipment manufacturers and designers are responsible to ensure that their systems, and any Future Technology Devices International Ltd
(FTDI) devices incorporated in their systems, meet all applicable safety, regulatory and system-level performance requirements. All application-related
information in this document (including application descriptions, suggested FTDI devices and other materials) is provided for reference only. While FTDI
has taken care to assure it is accurate, this information is subject to customer confirmation, and FTDI disclaims all liability for system designs and for any
applications assistance provided by FTDI. Use of FTDI devices in life support and/or safety applications is entirely at the user’s risk, and the user agrees to
defend, indemnify and hold harmless FTDI from any and all damages, claims, suits or expense resulting from such use. This document is subject to change
without notice. No freedom to use patents or other intellectual property rights is implied by the publication of this document. Neither the whole nor any part
of the information contained in, or the product described in this document, may be adapted or reproduced in any material or electronic form without the prior
written consent of the copyright holder. Future Technology Devices International Ltd, Unit 1, 2 Seaward Place, Centurion Business Park, Glasgow G41
1HH, United Kingdom. Scotland Registered Company Number: SC136640
10
Copyright © 2012 Future Technology Devices International Limited
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
Appendix A – List of Tables and Figures
List of Figures
Figure 2-1 – Using the TTL-232R-RPi Generic Cable ................................................................................... 4
Figure 4-1 – TTL-232R-RPi Debug cable Pin Out ......................................................................................... 5
Figure 4-2 – TTL-232R-RPi Debug cable, Single Pole Header Mechanical Details ................................... 5
Figure 5-1 – TTL-232R-RPi Debug cable, connection diagram ................................................................... 7
Figure 7-1 – Circuit Schematic of PCB Used in the TTL 232R-RPi Debug cable ...................................... 8
List of Tables
Table 1-1 – USB-RS232 Adapter Ordering Information ............................................................................... 2
Table 4-1 – TTL-232R-RPi Debug cable Signal Descriptions ...................................................................... 6
Table 4-2 – TTL-232R-RPi Debug cable Operating Parameters .................................................................. 6
Table 4-3 – TTL-232R- RPi Debug cable I/O Pin Characteristics ................................................................ 6
Table 8-1 – Default Internal EEPROM Configuration ................................................................................... 9
Copyright © 2012 Future Technology Devices International Limited
10
TTL-232R-RPi
Version 1.0
Document Reference No.: FT_000722
Clearance No.: FTDI# 296
Appendix B – Revision History
Document Title:
DS_TTL-232R-RPi
Document Reference No.:
FT_000722
Clearance No.:
FTDI# 296
Product Page:
http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm
Document Feedback:
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Version 1.0
Initial Datasheet Released
Copyright © 2012 Future Technology Devices International Limited
15/06/12
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