spi-tools

This package contains some simple command line tools to help using Linux spidev devices.

Version 1.0.2

Content

spi-config

Query or set the SPI configuration (mode, speed, bits per word, etc.)

spi-pipe

Send and receive data simultaneously to and from a SPI device.

License

The tools are released under the GPLv2 license. See LICENSE file for details.

Author

Christophe Blaess https://www.blaess.fr/christophe

Installation

There's two ways to install spi-tools: using Autotools or using Cmake.

Autotools

First, get the latest version on https://github.com/cpb-/spi-tools.git. Then enter the directory and execute:

$ autoreconf -fim
$ ./configure
$ make

Then you can run make install (probably with sudo) to install them and the man pages.

If you have to use a cross-compilation toolchain, add the --host option to the ./configure command, as in ./configure --host=arm-linux. This is the prefix to be inserted before all the toolchain commands (giving for example arm-linux-gcc).

You can use make uninstall (with sudo) to remove the installed files.

Cmake

Usage

spi-config usage

options

• -d --device=<dev> use the given spi-dev character device.
• -q --query print the current configuration.
• -m --mode=[0-3] use the selected spi mode.
• -l --lsb={0,1} LSB first (1) or MSB first (0).
• -b --bits=[7...] bits per word.
• -s --speed=<int> set the speed in Hz.
• -r --spirdy={0,1} set the SPI_READY spi mode flag.
• -w --wait block, keeping the file descriptor open.
• -h --help help screen.
• -v --version display the version number.

Read the current configuration

$ spi-config -d /dev/spidev0.0 -q
/dev/spidev0.0: mode=0, lsb=0, bits=8, speed=500000
$

Change the clock frequency and read it again

$ spi-config -d /dev/spidev0.0 -s 10000000
$ spi-config -d /dev/spidev0.0 -q
/dev/spidev0.0: mode=0, lsb=0, bits=8, speed=10000000
$

Note: on some platforms, the speed is reset to a default value when the file descriptor is closed. To avoid this, one can use the -w option that keep the file descriptor open. For example:

$ spi-config -d /dev/spidev0.0 -s 10000000 -w &
$ PID=$!

And when you don't need the SPI device anymore:

$ kill $PID

spi-pipe usage

Options

• -d --device=<dev> use the given spi-dev character device.
• -m --mode=[0-3] use the selected spi mode.
• -s --speed=<speed> Maximum SPI clock rate (in Hz).
• -l --lsb={0,1} LSB first (1) or MSB first (0).
• -B --bits=[7...] bits per word.
• -r --spirdy={0,1} set the SPI_READY spi mode flag.
• -b --blocksize=<int> transfer block size in byte.
• -n --number=<int> number of blocks to transfer.
• -h --help help screen.
• -v --version display the version number.

Send and receive simultaneously

Sending data from command-1 to SPI link and receiving data from SPI link to command-2

$ command_1 | spi-pipe -d /dev/spidev0.0 | command_2

Note that command_1, command_2 and spi-pipe run simultaneously in three parallel processes.

Send data through the SPI link

$ command_1 | spi-pipe -d /dev/spidev0.0

Receive data from the SPI link

$ spi-pipe -d /dev/spidev0.0 < /dev/zero | command_2

You can also use command_2 < /dev/spidev0.0 but with spi-pipe you control what is sent to the device (always 0 in this case).

Read 40 blocks of 4 bytes from the SPI link

$ spi-pipe -d /dev/spidev0.0 -b 4 -n 40 < /dev/zero | command_2

Send binary commands through the SPI link

You can use the shell printf command to format binary data to send.

For example, to send the bytes sequence 0x01-0x82-0xF3 and see the reply, use:

$ printf '\x01\x82\xF3' | spi-pipe -d /dev/spidev0.0 | hexdump -C