https://github.com/rm-hull/spidev-test
https://github.com/rm-hull/spidev-test
Last synced: over 1 year ago
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- Host: GitHub
- URL: https://github.com/rm-hull/spidev-test
- Owner: rm-hull
- License: gpl-2.0
- Created: 2017-02-05T18:08:40.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2022-06-02T18:01:21.000Z (about 4 years ago)
- Last Synced: 2024-10-03T12:17:41.040Z (almost 2 years ago)
- Language: C
- Size: 13.7 KB
- Stars: 98
- Watchers: 10
- Forks: 39
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# spidev-test
A copy of https://github.com/torvalds/linux/blob/master/tools/spi/spidev_test.c
(becasue I can never find it when I need it), with the following changes:
* The default device was changed from `/dev/spidev1.1` to `/dev/spidev0.0`
* The SPI modes were changed from `SPI_IOC_WR_MODE32` and `SPI_IOC_RD_MODE32` to
`SPI_IOC_WR_MODE` and `SPI_IOC_RD_MODE` respectively.
## What is this for?
If you are experiencing issues with the [SPI](https://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus)
bus on Raspberry Pi or other Linux-based single-board computers, this program
(plus a single jumper or wire) will confirm whether SPI is working properly.
## Building on Raspberry Pi / Orange Pi
Download the code from github and compile with:
$ git clone https://github.com/rm-hull/spidev-test
$ cd spidev-test
$ gcc spidev_test.c -o spidev_test
## Enabling SPI on the Raspberry Pi
By default, the SPI kernel driver is **NOT** enabled on the Raspberry Pi Raspian image.
You can confirm whether it is enabled using the shell commands below::
$ lsmod | grep -i spi
spi_bcm2835 7424 0
Depending on the hardware/kernel version, this may report **spi_bcm2807** rather
than **spi_bcm2835** - either should be adequate.
Check whether the devices are successfully installed in `/dev`:
$ ls -l /dev/spi*
crw------- 1 root root 153, 0 Jan 1 1970 /dev/spidev0.0
crw------- 1 root root 153, 1 Jan 1 1970 /dev/spidev0.1
If you have no `/dev/spi` files and nothing is showing using `lsmod` then this
implies the kernel SPI driver is not loaded. Enable the SPI as follows (steps
taken from https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial#spi-on-pi):
1. Run `sudo raspi-config`
2. Use the down arrow to select `9 Advanced Options`
3. Arrow down to `A6 SPI.`
4. Select **yes** when it asks you to enable SPI,
5. Also select **yes** when it asks about automatically loading the kernel module.
6. Use the right arrow to select the **** button.
7. Select **yes** when it asks to reboot.
After rebooting re-check that the `lsmod | grep -i spi` command shows whether
SPI driver is loaded before proceeding. If you are stil experiencing problems, refer to the official
Raspberry Pi [SPI troubleshooting guide](https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md#troubleshooting)
## Testing the SPI bus
On RPi and other pin-compatible boards, connect pin 19 (BCM 10 = MOSI) to
pin 21 (BCM 9 = MISO) to form a loopback connection. See https://pinout.xyz
for further details.
Run the compiled executable:
$ ./spidev_test -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@....?..................?.
RX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@....?..................?.
_(run with `sudo` if it shows an error about permissions)_
## Interpretting the results
With the MOSI _(master out, slave in)_ pin connected to the MISO _(master in,
slave out)_, the received data should be exactly the same as the transmitted data,
as in the above example.
If received data is all zero as below:
$ ./spidev_test -v
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@....?..................?.
RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................
This implies the pins MOSI and MISO aren't connected.
## Program options
Use the `-?` flag to show all the available options:
$ ./spidev_test -?
usage: ./spidev_test [-DsbdlHOLC3]
-D --device device to use (default /dev/spidev1.1)
-s --speed max speed (Hz)
-d --delay delay (usec)
-b --bpw bits per word
-i --input input data from a file (e.g. "test.bin")
-o --output output data to a file (e.g. "results.bin")
-l --loop loopback
-H --cpha clock phase
-O --cpol clock polarity
-L --lsb least significant bit first
-C --cs-high chip select active high
-3 --3wire SI/SO signals shared
-v --verbose Verbose (show tx buffer)
-p Send data (e.g. "1234\xde\xad")
-N --no-cs no chip select
-R --ready slave pulls low to pause
-2 --dual dual transfer
-4 --quad quad transfer