range Pi User Manual Copyright reserved by Shenzhen Xunlong Software Co., Ltd
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3) First check whether there is a spidev3.0 device node in the Linux system. If it exists,
it means that SPI3 has been set up and can be used directly
orangepi@orangepi:~$ ls /dev/spidev3.0
/dev/spidev3.0
4) Then you can use the spidev_test.py program in the examples to test the loopback
function of the SPI. The spidev_test.py program needs to specify the following two
parameters:
a. --channel:Specify the channel number of SPI
b. --port:Specify the port number of the SPI
5) Do not short-circuit the mosi and miso pins of SPI3, the output of running
spidev_test.py is as follows, you can see that the data of TX and RX are inconsistent
root@orangepi:~/wiringOP-Python# cd examples
root@orangepi:~/wiringOP-Python/examples# python3 spidev_test.py \
--channel 3 --port 0
spi mode: 0x0
max speed: 500000 Hz (500 KHz)
Opening device /dev/spidev3.0
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 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
FF FF FF FF FF FF FF FF |.................|
6) Then use the Dupont wire to short-circuit the two pins of txd (pin 19 in the 40pin
interface) and rxd (pin 21 in the 40pin interface) of SPI3 and then run the output of
spidev_test.py as follows, you can see The data sent and received are the same, indicating
that the SPI3 loopback test is normal
root@orangepi:~/wiringOP-Python# cd examples
root@orangepi:~/wiringOP-Python/examples# python3 spidev_test.py \
--channel 3 --port 0
spi mode: 0x0
max speed: 500000 Hz (500 KHz)
Opening device /dev/spidev3.0
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