The use of Cubieboard SPI

Toss for nearly one months of SPI communication (if it is big God's words estimated early to get out, but the harvest is quite large, at least almost understand the SPI subsystem), finally small results, cubieboard on the SPI mouth, is also called through, Here to thank Hipboi and so on the network of the Great God to help me, thanks to CCTV. First of all, related to SPI communications, there are mainly three code files, spi_sunxi.c,spi.c,spidev.c. SPI_SUNXI.C is mainly the SPI drive of A10, SPI.C is the center of the whole SPI subsystem, which provides interface for SPI_SUNXI.C and SPIDEV.C, and also plays a role of bridge. SPIDEV.C is mainly used to provide the interface for user space to read and write SPI, that is, to generate spi0.0 and so on under/dev/. To enable the full log SPI to communicate, the underlying code is already written, and we only need to make the appropriate changes to the configuration file (Script.fex). spi_used = 1 Spi_cs_bitmap = 1 Spi_cs0 = port:pi10<3><default><default><default> SPI_SCLK = port:pi11<3><default><default><default> Spi_mosi = port:pi12<3><default><default><default> Spi_miso = port:pi13<3><default><default><default> Among them, the need is particularly important, understanding SPI_CS0 = port:pi10<3><default><default><default> Port:pi10 means to use PI10 this pin,<3> this bracket, the value can be 0~7, if configured to 0, this pin represents the Gpio input, 1 represents Gpio Output, as for the value of 2~7, according to the different pins, different values have different functions but 2~7 is mainly representative of the reuse of ports, as to what the reuse into the port, please refer to [Url]http://linux-sunxi.org/a10/pio[/url] You can see from the diagram, if you want to use SPI, you should use MUX2, and my Fex file, the default is <3&gt, Port Multiplexing became UART, so this place must change, I just because this place has not changed, so the whole for a long time. [Spi_devices] Spi_dev_num = 1 [Spi_board0] Modalias = "Spidev" Max_speed_hz = 12000000 Bus_num = 0 Chip_select = 0 mode = 3 Full_Duplex = 0 Manual_cs = 0 This should be noted Modalias, which is the same name as in spidev.c. Name = "Spidev". Specific knowledge of the driver should know why, there is the full log of the SPI does not support Full-duplex. After the above configuration is complete, oneself writes an application casually, or writes the point value in the/dev/spidev0.0, should have the reaction