SPISlave Class Reference

A SPI slave, used for communicating with a SPI master device. More...

#include <SPISlave.h>

Inheritance diagram for SPISlave:

Public Member Functions
	SPISlave (PinName mosi, PinName miso, PinName sclk, PinName ssel)
	Create a SPI slave connected to the specified pins. More...
	SPISlave (const spi_pinmap_t &pinmap)
	Create a SPI slave connected to the specified pins. More...
	~SPISlave ()
	Destructor. More...
void	format (int bits, int mode=0)
	Configure the data transmission format. More...
int	receive (void)
	Polls the SPI to see if data has been received. More...
int	read (void)
	Retrieve data from receive buffer as slave. More...
void	reply (int value)
	Fill the transmission buffer with the value to be written out as slave on the next received message from the master. More...

Detailed Description

A SPI slave, used for communicating with a SPI master device.

The default format is set to 8 bits, mode 0.

Note

Synchronization level: Not protected

Example of how to reply to a SPI master as slave:

#include "mbed.h"
 
SPISlave device(SPI_MOSI, SPI_MISO, SPI_SCLK, SPI_CS);
 
int main() {
    device.reply(0x00);              // Prime SPI with first reply
    while(1) {
        if(device.receive()) {
            int v = device.read();   // Read byte from master
            v = (v + 1) % 0x100;     // Add one to it, modulo 256
            device.reply(v);         // Make this the next reply
        }
    }
}

Definition at line 59 of file SPISlave.h.

Constructor & Destructor Documentation

SPISlave() [1/2]

SPISlave	(	PinName	mosi,
		PinName	miso,
		PinName	sclk,
		PinName	ssel
	)

Create a SPI slave connected to the specified pins.

Note

Either mosi or miso can be specified 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.

SPISlave() [2/2]

SPISlave

(

const spi_pinmap_t &

pinmap

)

Create a SPI slave connected to the specified pins.

Note

Either mosi or miso can be specified as NC if not used.

Parameters

pinmap

reference to structure which holds static pinmap.

~SPISlave()

~SPISlave

(

)

Destructor.

Frees the SPI peripheral so it can be used elsewhere.

Member Function Documentation

format()

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

receive()

int receive

(

void

)

Polls the SPI to see if data has been received.

Returns

Presence of received data.

Return values

0	No data waiting.
1	Data waiting.

read()

int read

(

void

)

Retrieve data from receive buffer as slave.

Returns

The data in the receive buffer.

reply()

void reply

(

int

value

)

Fill the transmission buffer with the value to be written out as slave on the next received message from the master.

Parameters

value

The data to be transmitted next.