SPI

Detailed Description

SPI Driver.

This driver allows multiple clients to share the SPI bus. This assumes that all clients use the same SPI configuration. If that isn't the case we'll need to introduce client handles or something.

Clients can queue an SPI transfer with the SPI_QueueTransfer() method. The callback argument can be used to specify a callback to be run before and after the transfer is performed. This callback can be used to set the relevant chip-enable line.

Files
file	spi.h
	SPI Driver.

Typedefs
typedef void(*	SPI_Callback )(SPIEventType event)
	The callback run before and after the SPI transfer begins. More...

Enumerations
enum	SPIEventType { SPI_BEGIN_TRANSFER, SPI_COMPLETE_TRANSFER }
	SPI Event types.

Functions
bool	SPI_QueueTransfer (const uint8_t *output, unsigned int output_length, uint8_t *input, unsigned int input_length, SPI_Callback callback)
	Queue an SPI transfer. More...
void	SPI_Initialize ()
	Initialize the SPI driver.
void	SPI_Tasks ()
	The tasks function, this should be called from the main event loop.

Typedef Documentation

typedef void(* SPI_Callback)(SPIEventType event)

The callback run before and after the SPI transfer begins.

Parameters

event

The type of SPI event that occurs.

Function Documentation

bool SPI_QueueTransfer	(	const uint8_t *	output,
		unsigned int	output_length,
		uint8_t *	input,
		unsigned int	input_length,
		SPI_Callback	callback
	)

Queue an SPI transfer.

Parameters

output	The output buffer to send, may be NULL.
output_length	The size of the output buffer.
input	The location to store received data, may be NULL.
input_length	The length of the input data buffer.
callback	The callback run prior and post this transfer.

Returns

True if the transfer was scheduled, false if the queue was full.

This queues a write / read SPI operation. First the data in output will be sent, then input_length worth of data will be read while 0s are sent. Both stages are optional.

The total number of bytes sent will be the sum of (output_length, input_length).