A SPI Master, used for communicating with SPI slave devices. More...

#include <SPI.h>

Public Member Functions
	SPI (PinName mosi, PinName miso, PinName sclk, PinName ssel=NC)
	Create a SPI master connected to the specified pins.
void	format (int bits, int mode=0)
	Configure the data transmission format.
void	frequency (int hz=1000000)
	Set the spi bus clock frequency.
virtual int	write (int value)
	Write to the SPI Slave and return the response.
virtual int	write (const char tx_buffer, int tx_length, char rx_buffer, int rx_length)
	Write to the SPI Slave and obtain the response.
virtual void	lock (void)
	Acquire exclusive access to this SPI bus.
virtual void	unlock (void)
	Release exclusive access to this SPI bus.
void	set_default_write_value (char data)
	Set default write data SPI requires the master to send some data during a read operation.
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
void	irq_handler_asynch (void)
	SPI IRQ handler.
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.
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.
Private Member Functions
	MBED_DEPRECATED ("Invalid copy construction of a NonCopyable resource.") NonCopyable(const NonCopyable &)
	NonCopyable copy constructor.
	MBED_DEPRECATED ("Invalid copy assignment of a NonCopyable resource.") NonCopyable &operator
	NonCopyable copy assignment operator.

Detailed Description

A SPI Master, used for communicating with SPI slave devices.

The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz

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

Note:: Synchronization level: Thread safe

Example:

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

 #include "mbed.h"

 // hardware ssel (where applicable)
 //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel

 // software ssel
 SPI device(p5, p6, p7); // mosi, miso, sclk
 DigitalOut cs(p8); // ssel

 int main() {
     // hardware ssel (where applicable)
     //int response = device.write(0xFF);

     device.lock();
     // software ssel
     cs = 0;
     int response = device.write(0xFF);
     cs = 1;
     device.unlock();

 }

Definition at line 76 of file SPI.h.

Constructor & Destructor Documentation

SPI	(	PinName	mosi,
		PinName	miso,
		PinName	sclk,
		PinName	ssel = `NC`
	)

Create a SPI master connected to the specified pins.

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
ssel	SPI chip select pin

Definition at line 31 of file SPI.cpp.

Member Function Documentation

void abort_all_transfers ( )

Clear the transaction buffer and abort on-going transfer.

Definition at line 157 of file SPI.cpp.

void abort_transfer ( void )

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

Definition at line 140 of file SPI.cpp.

void clear_transfer_buffer ( )

Clear the transaction buffer.

Definition at line 150 of file SPI.cpp.

void dequeue_transaction ( ) [protected]

Dequeue a transaction.

Definition at line 217 of file SPI.cpp.

void format	(	int	bits,
		int	mode = `0`
	)

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 47 of file SPI.cpp.

void frequency ( int hz = 1000000 )

Set the spi bus clock frequency.

Parameters:

hz	SCLK frequency in hz (default = 1MHz)

Definition at line 62 of file SPI.cpp.

void irq_handler_asynch ( void ) [protected]

SPI IRQ handler.

Definition at line 229 of file SPI.cpp.

void lock ( void ) [virtual]

Acquire exclusive access to this SPI bus.

Definition at line 115 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]`

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 172 of file SPI.cpp.

void set_default_write_value ( char data )

Set default write data SPI requires the master to send some data during a read operation.

Different devices may require different default byte values. For example: A SD Card requires default bytes to be 0xFF.

Parameters:

data	Default character to be transmitted while read operation

Definition at line 123 of file SPI.cpp.

int set_dma_usage ( DMAUsage usage )

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 163 of file SPI.cpp.

void start_transaction ( transaction_t * data ) [protected]

Start a new transaction.

Parameters:

data	Transaction data

Definition at line 212 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]`

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 201 of file SPI.cpp.

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]`

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 131 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`
	)

Start non-blocking SPI transfer using 8bit buffers.

This function locks the deep sleep until any event has occured

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 172 of file SPI.h.

void unlock ( void ) [virtual]

Release exclusive access to this SPI bus.

Definition at line 119 of file SPI.cpp.

int write	(	const char *	tx_buffer,
		int	tx_length,
		char *	rx_buffer,
		int	rx_length
	)		`[virtual]`

Write to the SPI Slave and obtain the response.

The total number of bytes sent and recieved will be the maximum of tx_length and rx_length. The bytes written will be padded with the value 0xff.

Parameters:

tx_buffer	Pointer to the byte-array of data to write to the device
tx_length	Number of bytes to write, may be zero
rx_buffer	Pointer to the byte-array of data to read from the device
rx_length	Number of bytes to read, may be zero

Returns:: The number of bytes written and read from the device. This is maximum of tx_length and rx_length.

Definition at line 107 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

Definition at line 99 of file SPI.cpp.

Type:	Library
Created:	15 Jan 2020
Imports:	12
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	0
Followers:	2

SPI Class Reference
[Drivers]

Public Member Functions

Protected Member Functions

Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

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SPI Class Reference [Drivers]

Public Member Functions

Protected Member Functions

Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Repository toolbox

Repository details

Important Information for this Arm website

Access Warning

SPI Class Reference
[Drivers]