SPI Master Synchronous Driver

Summary of the API's Functional Features

The API provides functions to:

Initialize and deinitialize the driver and associated hardware
Register I/O descriptor
Enable or disable SPI master
Data transfer: transmission, reception, and full-duplex

Summary of Configuration Options

Below is a list of the main SPI master parameters that can be configured in START. Many of these parameters are used by the spi_m_sync_init function when initializing the driver and underlying hardware. Most of the initial values can be overridden and changed runtime by calling the appropriate API functions.

Select character size
Set SPI baudrate
Which clock source is used

Driver Implementation Description

After SPI hardware initialization, the spi_m_sync_get_io_descriptor function is needed to register an I/O descriptor. Then enable the SPI hardware. At the end, control the slave select (SS) pin, and start the read/write operation.

Limitations

The slave select (SS) is not automatically inserted during read/write/transfer, user must use I/O to control the devices' SS.

Example of Usage

The following shows a simple example of using the SPI master. The SPI master must have been initialized by spi_m_sync_init. This initialization will configure the operation of the SPI master.

The example enables the SPI master, and finally starts a writing operation to the slave.

/** * Example of using SPI_0 to write "Hello World" using the I/O abstraction. */static uint8_t example_SPI_0[12] = "Hello World!";void SPI_0_example(void){    struct io_descriptor *io;    spi_m_sync_get_io_descriptor(&SPI_0, &io);    spi_m_sync_enable(&SPI_0);    /* Control the slave select (SS) pin */    //gpio_set_pin_level(SPI_0_SS, false);    io_write(io, example_SPI_0, 12);    /* Control the slave select (SS) pin */    //gpio_set_pin_level(SPI_0_SS, true);}

Dependencies

SPI master peripheral and its related I/O lines and clocks