Arduino Communications Device Naming with udev

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This article covers the installation and basic usage of the Bus Pirate.

The Bus Pirate is a versatile tool for communicating with various hardware.

Interfacing a new microchip can be a hassle. Breadboarding a circuit, writing code, hauling out the programmer, or maybe even prototyping a PCB. We never seem to get it right on the first try.

The ‘Bus Pirate’ is a universal bus interface that talks to most chips from a PC serial terminal, eliminating a ton of early prototyping effort when working with new or unknown chips. Many serial protocols are supported at 0-5.5volts, more can be added. See more at the google code site for the Bus Pirate.


Note: All scripts will assume that there is a '/dev/arduino_1'.

The drivers for the FTDI chip is included in the kernel, so it should be detected as soon as it's plugged in, and assigned to device /dev/ttyUSB[0-9]. To check where it got assigned, run:

 dmesg | grep FTDI

The output will contain a line that looks something like this:

 usb 1-4.4: FTDI USB Serial Device converter now attached to ttyUSB0


It can be annoying to have to look up what /dev/ttyUSB[0-9] the device gets assigned, so it's a good idea to add a simple udev rule that creates the renames the device when it is plugged in.

First of all, you will need to find out the serial number of FTDI chip on the bus pirate. This can be achieved by running the following, assuming your device is plugged in and was assigned to /dev/ttyUSB0:

 udevadm info --attribute-walk -n /dev/ttyUSB0

Now add/create the following file:

SUBSYSTEMS=="usb", ATTRS{serial}=="XXXXXXXX", ATTRS{product}=="FT232R USB UART", ATTRS{idProduct}=="6001", ATTRS{idVendor}=="0403", NAME="arduino_1"

Change 'ATTRS{serial}=="XXXXXXXX"' to the serial on your device and force udev to load the new rule:

 udevadm control --reload-rules

At this point, whenever you plug in the device, the device should be renamed to /dev/ttyUSB0


To communicate with the device, you can use any of the following, to name a few:

  • minicom
 minicom -b 115200 -8 -D /dev/buspirate
  • screen
 screen /dev/buspirate 115200 8N1
  • picocom
 picocom -b 115200 -p n -d 8 /dev/buspirate
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