ORANGE Pi 3B - Page 215

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range Pi User Manual Copyright reserved by Shenzhen Xunlong Software Co., Ltd

207

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