A SPI half-duplex master, used for communicating with SPI slave devices over a shared data line. More...

#include <SPIHalfDuplex.h>

Public Member Functions
	SPIHalfDuplex (PinName mosi, PinName miso, PinName sclk)
	Create a SPI half-duplex master connected to the specified pins.
virtual int	write (int value)
	Write to the SPI Slave and return the response.
void	slave_format (int sbits)
	Set the number of databits expected from the slave, from 4-16.
void	format (int bits, int mode=0)
	Configure the data transmission format.
void	frequency (int hz=1000000)
	Set the spi bus clock frequency.
virtual void	lock (void)
	Acquire exclusive access to this SPI bus.
virtual void	unlock (void)
	Release exclusive access to this SPI bus.
template<typename Type >
int	transfer (const Type tx_buffer, int tx_length, Type rx_buffer, int rx_length, const event_callback_t &callback, int event=SPI_EVENT_COMPLETE)
	Start non-blocking SPI transfer using 8bit buffers.
void	abort_transfer ()
	Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
void	clear_transfer_buffer ()
	Clear the transaction buffer.
void	abort_all_transfers ()
	Clear the transaction buffer and abort on-going transfer.
int	set_dma_usage (DMAUsage usage)
	Configure DMA usage suggestion for non-blocking transfers.
Protected Member Functions
int	transfer (const void tx_buffer, int tx_length, void rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event)
	Common transfer method.
void	irq_handler_asynch (void)
	SPI IRQ handler.
int	queue_transfer (const void tx_buffer, int tx_length, void rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event)
void	start_transfer (const void tx_buffer, int tx_length, void rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event)
	Configures a callback, spi peripheral and initiate a new transfer.
void	start_transaction (transaction_t *data)
	Start a new transaction.
void	dequeue_transaction ()
	Dequeue a transaction.

Detailed Description

A SPI half-duplex master, used for communicating with SPI slave devices over a shared data line.

The default format is set to 8-bits for both master and slave, and a clock frequency of 1MHz

Most SPI devies will also require Chip Select and Reset signals. These can be controlled using <DigitalOut> pins.

Although this is for a shared data line, both MISO and MOSI are defined, and should be tied together externally to the mbed. This class handles the tri-stating of the MOSI pin.

Example:

 // Send a byte to a SPI half-duplex slave, and record the response

 #include "mbed.h"

 SPIHalfDuplex device(p5, p6, p7) // mosi, miso, sclk

 int main() {
     int respone = device.write(0xAA);
 }

Definition at line 42 of file SPIHalfDuplex.h.

Constructor & Destructor Documentation

SPIHalfDuplex	(	PinName	mosi,
		PinName	miso,
		PinName	sclk
	)

Create a SPI half-duplex master connected to the specified pins.

Pin Options: (5, 6, 7) or (11, 12, 13)

mosi or miso can be specfied as NC if not used

Parameters:

mosi	SPI Master Out, Slave In pin
miso	SPI Master In, Slave Out pin
sclk	SPI Clock pin
name	(optional) A string to identify the object

Definition at line 16 of file SPIHalfDuplex.cpp.

Member Function Documentation

void abort_all_transfers ( ) [inherited]

Clear the transaction buffer and abort on-going transfer.

Definition at line 116 of file SPI.cpp.

void abort_transfer ( void ) [inherited]

Abort the on-going SPI transfer, and continue with transfer's in the queue if any.

Definition at line 100 of file SPI.cpp.

void clear_transfer_buffer ( ) [inherited]

Clear the transaction buffer.

Definition at line 109 of file SPI.cpp.

void dequeue_transaction ( ) [protected, inherited]

Dequeue a transaction.

Definition at line 175 of file SPI.cpp.

void format	(	int	bits,
		int	mode = `0`
	)		`[inherited]`

Configure the data transmission format.

Parameters:

bits	Number of bits per SPI frame (4 - 16)
mode	Clock polarity and phase mode (0 - 3)

 mode | POL PHA
 -----+--------
   0  |  0   0
   1  |  0   1
   2  |  1   0
   3  |  1   1

Definition at line 42 of file SPI.cpp.

void frequency ( int hz = 1000000 ) [inherited]

Set the spi bus clock frequency.

Parameters:

hz	SCLK frequency in hz (default = 1MHz)

Definition at line 51 of file SPI.cpp.

void irq_handler_asynch ( void ) [protected, inherited]

SPI IRQ handler.

Definition at line 187 of file SPI.cpp.

void lock ( void ) [virtual, inherited]

Acquire exclusive access to this SPI bus.

Definition at line 81 of file SPI.cpp.

int queue_transfer	(	const void *	tx_buffer,
		int	tx_length,
		void *	rx_buffer,
		int	rx_length,
		unsigned char	bit_width,
		const event_callback_t &	callback,
		int	event
	)		`[protected, inherited]`

Parameters:

tx_buffer	The TX buffer with data to be transfered. If NULL is passed, the default SPI value is sent
tx_length	The length of TX buffer in bytes
rx_buffer	The RX buffer which is used for received data. If NULL is passed, received data are ignored
rx_length	The length of RX buffer in bytes
bit_width	The buffers element width
callback	The event callback function
event	The logical OR of events to modify

Returns:: Zero if a transfer was added to the queue, or -1 if the queue is full

Definition at line 131 of file SPI.cpp.

int set_dma_usage ( DMAUsage usage ) [inherited]

Configure DMA usage suggestion for non-blocking transfers.

Parameters:

usage The usage DMA hint for peripheral

Returns:: Zero if the usage was set, -1 if a transaction is on-going

Definition at line 122 of file SPI.cpp.

void slave_format ( int sbits )

Set the number of databits expected from the slave, from 4-16.

Parameters:

sbits Number of expected bits in the slave response

Definition at line 22 of file SPIHalfDuplex.cpp.

void start_transaction ( transaction_t * data ) [protected, inherited]

Start a new transaction.

Parameters:

data	Transaction data

Definition at line 170 of file SPI.cpp.

void start_transfer	(	const void *	tx_buffer,
		int	tx_length,
		void *	rx_buffer,
		int	rx_length,
		unsigned char	bit_width,
		const event_callback_t &	callback,
		int	event
	)		`[protected, inherited]`

Configures a callback, spi peripheral and initiate a new transfer.

Parameters:

tx_buffer	The TX buffer with data to be transfered. If NULL is passed, the default SPI value is sent
tx_length	The length of TX buffer in bytes
rx_buffer	The RX buffer which is used for received data. If NULL is passed, received data are ignored
rx_length	The length of RX buffer in bytes
bit_width	The buffers element width
callback	The event callback function
event	The logical OR of events to modify

Definition at line 160 of file SPI.cpp.

int transfer	(	const Type *	tx_buffer,
		int	tx_length,
		Type *	rx_buffer,
		int	rx_length,
		const event_callback_t &	callback,
		int	event = `SPI_EVENT_COMPLETE`
	)		`[inherited]`

Start non-blocking SPI transfer using 8bit buffers.

Parameters:

tx_buffer	The TX buffer with data to be transfered. If NULL is passed, the default SPI value is sent
tx_length	The length of TX buffer in bytes
rx_buffer	The RX buffer which is used for received data. If NULL is passed, received data are ignored
rx_length	The length of RX buffer in bytes
callback	The event callback function
event	The logical OR of events to modify. Look at spi hal header file for SPI events.

Returns:: Zero if the transfer has started, or -1 if SPI peripheral is busy

Definition at line 142 of file SPI.h.

int transfer	(	const void *	tx_buffer,
		int	tx_length,
		void *	rx_buffer,
		int	rx_length,
		unsigned char	bit_width,
		const event_callback_t &	callback,
		int	event
	)		`[protected, inherited]`

Common transfer method.

Parameters:

tx_buffer	The TX buffer with data to be transfered. If NULL is passed, the default SPI value is sent
tx_length	The length of TX buffer in bytes
rx_buffer	The RX buffer which is used for received data. If NULL is passed, received data are ignored
rx_length	The length of RX buffer in bytes
bit_width	The buffers element width
callback	The event callback function
event	The logical OR of events to modify

Returns:: Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full

Definition at line 91 of file SPI.cpp.

void unlock ( void ) [virtual, inherited]

Release exclusive access to this SPI bus.

Definition at line 85 of file SPI.cpp.

int write ( int value ) [virtual]

Write to the SPI Slave and return the response.

Parameters:

value Data to be sent to the SPI slave

Returns:: Response from the SPI slave

Reimplemented from SPI.

Definition at line 26 of file SPIHalfDuplex.cpp.

Type:	Program
Created:	22 Oct 2016
Imports:	2
Forks:	0
Commits:	10
Dependents:	0
Dependencies:	3
Followers:	1

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