# SPI操作 ## 預備配置 ### 主線內核 在DTS中使能SPI功能： spi是平臺驅動，dts中寫的設備的compatible字段即是需要匹配的驅動名。這里使用用戶空間驅動SPIDEV。 /arch/arm/boot/dts/sun8i-v3s-licheepi-zero.dts ~~~ &spi0 { pinctrl-names = "default"; pinctrl-0 = <&spi0_pins>; status = "okay"; #address-cells=<1>; #size-cells=<0>; spidev@0x00 { compatible = "spidev"; spi-max-frequency = <100000000>; reg = <0>; }; }; ~~~ 在內核配置中使能spidev驅動： ### BSP內核 在fex中修改： ~~~ [spi_devices] spi_dev_num = 1 [spi_board0] modalias = "spidev" max_speed_hz = 12000000 bus_num = 0 chip_select = 0 mode = 0 ~~~ ~~~ #define SPI_MODE_0 (0|0) #define SPI_MODE_1 (0|SPI_CPHA) //相位 #define SPI_MODE_2 (SPI_CPOL|0) //極性 #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) ~~~ bsp驅動中限制最高SPI速率80M 以上操作完成后，開啟系統，會看到/dev/spidev0.0設備 ## C語言操作 linux-3.4/Documentation/spi/spidev_test.c 該例程可以設置spi參數，并發送了一堆測試數據。 ~~~ " -D --device device to use (default /dev/spidev1.1)\n" " -s --speed max speed (Hz)\n" " -d --delay delay (usec)\n" " -b --bpw bits per word \n" " -l --loop loopback\n" " -H --cpha clock phase\n" " -O --cpol clock polarity\n" " -L --lsb least significant bit first\n" " -C --cs-high chip select active high\n" " -3 --3wire SI/SO signals shared\n"); ~~~ ~~~ # ./spidev_test -D /dev/spidev0.0 -s 50000000 spi mode: 0 bits per word: 8 max speed: 50000000 Hz (50000 KHz) 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 DE AD BE EF BA AD F0 0D ~~~ 發送接收示例 linux-3.4/Documentation/spi/spidev_fdx.c usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n" ./spidev_fdx -m 發送長度 -r 接收長度 ## python操作 ## 參考資料 http://blog.csdn.net/DroidPhone/article/details/23367051 http://blog.csdn.net/DroidPhone/article/details/23932447 http://blog.csdn.net/droidphone/article/details/24353293 http://blog.csdn.net/DroidPhone/article/details/24663659 http://www.embedu.org/column/column367.htm