SPI example with Raspberry Pi and another MCU

Question

I've never used SPI before (for serial communication) and was wondering if any experienced Pi users out there know if the Pi board can use SPI to send and receive data to other MCUs on different boards.

If so, do these other boards need to be Pi's as well? Or can it be any other SPI-capable board?

How does SPI communication work on a Pi? Does it work in the form of user-level terminal commands, like:

// Turn a green LED on
send_to_spi 0x39943

Or is it something that has to be written in C and exist inside a running application? Any concrete examples or articles with concrete examples are greatly appreciated. Thanks in advance.

Answer 1

It is possible to connect the RPI to other devices via spi. You need to enable the kernel module and allow yourself access to the device.

sudo modprobe spi_bcm2708
sudo chown `id -u`.`id -g` /dev/spidev0.*

Then you can use this c file to test the dpi-device: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob_plain;f=Documentation/spi/spidev_test.c

Have a look at these links:

https://projects.drogon.net/understanding-spi-on-the-raspberry-pi/

http://mitchtech.net/raspberry-pi-arduino-spi/

http://elinux.org/RPi_Low-level_peripherals

Best of luck BjB