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/* mbed Microcontroller Library - SPIHalfDuplex
* Copyright (c) 2010-2011 ARM Limited. All rights reserved.
*/
#ifndef MBED_SPIHALFDUPLEX_H
#define MBED_SPIHALFDUPLEX_H
#include "platform.h"
#if DEVICE_SPI
#include "SPI.h"
namespace mbed {
/** 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:
* @code
* // 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);
* }
* @endcode
*/
class SPIHalfDuplex : public SPI {
public:
/** 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
*
* @param mosi SPI Master Out, Slave In pin
* @param miso SPI Master In, Slave Out pin
* @param sclk SPI Clock pin
* @param name (optional) A string to identify the object
*/
SPIHalfDuplex(PinName mosi, PinName miso, PinName sclk);
/** Write to the SPI Slave and return the response
*
* @param value Data to be sent to the SPI slave
*
* @returns
* Response from the SPI slave
*/
virtual int write(int value);
/** Set the number of databits expected from the slave, from 4-16
*
* @param sbits Number of expected bits in the slave response
*/
void slave_format(int sbits);
protected:
PinName _mosi;
PinName _miso;
int _sbits;
}; // End of class
} // End of namespace mbed
#endif
#endif
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