SPI

SPI library. More...

Classes
struct	SpiSettings
	SPI settings struct. More...

Macros
#define	SPI_TIMEOUT_MS   100U
	Maximum time permitted for a SPI transaction.
#define	SPI_MAX_NUM_DATA   32U
	None of our SPI transactions should need to be longer than 32 bytes.
#define	spi_tx(spi, tx_data, tx_len)   spi_exchange(spi, tx_data, tx_len, NULL, 0U)
	Transmit data from the SPI port. More...
#define	spi_rx(spi, rx_data, rx_len)   spi_exchange(spi, NULL, 0U, rx_data, rx_len)
	Receive data from the SPI port. More...

Enumerations
enum	SpiPort { SPI_PORT_1 = 0 , SPI_PORT_2 , SPI_PORT_3 , NUM_SPI_PORTS }
	SPI Port selection. More...
enum	SpiMode {   SPI_MODE_0 = 0 , SPI_MODE_1 , SPI_MODE_2 , SPI_MODE_3 ,   NUM_SPI_MODES }
	SPI Mode selection. More...

Functions
StatusCode	spi_init (SpiPort spi, const SpiSettings *settings)
	Initialize SPI instance. More...
StatusCode	spi_exchange (SpiPort spi, uint8_t *tx_data, size_t tx_len, uint8_t *rx_data, size_t rx_len)
	Performs a SPI data exchange. More...

Detailed Description

SPI library.

Macro Definition Documentation

spi_rx

#define spi_rx	(		spi,
			rx_data,
			rx_len
	)		spi_exchange(spi, NULL, 0U, rx_data, rx_len)

Receive data from the SPI port.

This method will only receive data, and will not send any data

Parameters

spi	Specifies which SPI port performs the receive
rx_data	Pointer to a buffer to receive data
rx_len	Length of the data to receive

spi_tx

#define spi_tx	(		spi,
			tx_data,
			tx_len
	)		spi_exchange(spi, tx_data, tx_len, NULL, 0U)

Transmit data from the SPI port.

This method will only send data, and will discard the response bytes

Parameters

spi	Specifies which SPI port performs the transmit
tx_data	Pointer to a buffer to transmit data
tx_len	Length of the data to transmit

Enumeration Type Documentation

SpiMode

enum SpiMode

SPI Mode selection.

Enumerator
SPI_MODE_0	CPOL: 0 CPHA: 0. Sampled on rising edge. Idle low
SPI_MODE_1	CPOL: 0 CPHA: 1. Sampled on falling edge. Idle low
SPI_MODE_2	CPOL: 1 CPHA: 0. Sampled on falling edge. Idle high
SPI_MODE_3	CPOL: 1 CPHA: 1. Sampled on rising edge. Idle high
NUM_SPI_MODES	Number of SPI Modes

SpiPort

enum SpiPort

SPI Port selection.

Enumerator
SPI_PORT_1	CS: PA4, SCLK: PA5, SDI: PA6, and SDO: PA7
SPI_PORT_2	CS: PB12, SCLK: PB13, SDI: PB14, and SDO: PB15
SPI_PORT_3	CS: PA15, SCLK: PB3, SDI: PB4, and SDO: PB5
NUM_SPI_PORTS	Number of SPI Ports

Function Documentation

spi_exchange()

StatusCode spi_exchange	(	SpiPort	spi,
		uint8_t *	tx_data,
		size_t	tx_len,
		uint8_t *	rx_data,
		size_t	rx_len
	)

Performs a SPI data exchange.

Half-duplex communication where it transmits first, then receives. It will first pull the CS low, transmit the data, then receive data, and finally pull CS high.

Parameters

spi	Specifies which SPI port performs the exchange
tx_data	Pointer to a buffer to transmit data
tx_len	Length of the data to transmit
rx_data	Pointer to a buffer to receive data
rx_len	Length of the data to receive

Returns

STATUS_CODE_OK if data exchange succeeded STATUS_CODE_INVALID_ARGS if one of the parameters are incorrect STATUS_CODE_INTERNAL_ERROR if HAL transmission/receiving fails STATUS_CODE_TIMEOUT if transmission/receiving takes too long

spi_init()

StatusCode spi_init	(	SpiPort	spi,
		const SpiSettings *	settings
	)

Initialize SPI instance.

Prescalers on STM32 must be a power of 2, so the actual baudrate may not be as exactly as requested.

Parameters

spi	Specifies which SPI port to initialize
settings	Pointer to SPI initialization settings

Returns

STATUS_CODE_OK if initialization succeeded STATUS_CODE_INVALID_ARGS if one of the parameters are incorrect STATUS_CODE_INTERNAL_ERROR if HAL initialization fails STATUS_CODE_RESOURCE_EXHAUSTED if already initialized