SPIHalfDuplex.cpp

00001 /* mbed Microcontroller Library - SPIHalfDuplex
00002  * Copyright (c) 2010-2011 ARM Limited. All rights reserved.
00003  */
00004 #include "SPIHalfDuplex.h"
00005 
00006 #if DEVICE_SPI
00007 
00008 #include "spi_api.h"
00009 #include "pinmap.h"
00010 
00011 #define GPIO_MODE 0
00012 #define SPI_MODE  2
00013 
00014 namespace mbed {
00015 
00016 SPIHalfDuplex::SPIHalfDuplex(PinName mosi, PinName miso, PinName sclk) : SPI(mosi, miso, sclk) {
00017     _mosi = mosi;
00018     _miso = miso;
00019     _sbits = _bits;
00020 }
00021 
00022 void SPIHalfDuplex::slave_format(int sbits) {
00023     _sbits = sbits;
00024 }
00025 
00026 int SPIHalfDuplex::write(int value) {
00027     int t_bits = _bits;
00028     pin_function(_mosi, SPI_MODE);
00029     int ret_val = SPI::write(value);
00030     if (ret_val != value) {
00031         return -1;
00032     }
00033     format(_sbits, _mode);
00034     pin_function(_mosi, GPIO_MODE);
00035     ret_val = SPI::write(0x55);
00036     format(t_bits, _mode);
00037     pin_function(_mosi, SPI_MODE);
00038     return ret_val;
00039 }
00040 
00041 } // end namespace mbed
00042 
00043 #endif