Diff: MCP23S17.cpp

Revision:

2:6144709f1700

Child:

3:089a2a754567

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP23S17.cpp	Sat Aug 21 14:46:59 2010 +0000
@@ -0,0 +1,61 @@
+/* MCP23S17 - drive the Microchip MCP23S17 16-bit Port Extender using SPI
+* Copyright (c) 2010 Romilly Cocking
+* Released under the MIT License: http://mbed.org/license/mit
+*
+* version 0.1
+*/
+
+#include "mbed.h"
+#include "MCP23S17.h"
+
+MCP23S17::MCP23S17(SPI& spi, PinName ncs, char writeOpcode) : _spi(spi), _ncs(ncs) {
+    _writeOpcode = writeOpcode;
+    _readOpcode = _writeOpcode | 1; // low order bit = 1 for read
+    _init();
+}
+
+char MCP23S17::_read(char address) {
+    _ncs = 0;
+    _spi.write(_readOpcode); 
+    _spi.write(address);
+    char result = _spi.write(0);
+    _ncs = 1;
+    return result;
+}
+
+void MCP23S17::_write(char address, char data) {
+    _ncs = 0;
+    _spi.write(_writeOpcode);
+    _spi.write(address);
+    _spi.write(data);
+    _ncs = 1;
+}
+
+void MCP23S17::_init() {
+    _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers
+}
+
+void MCP23S17::directionA(char direction) {
+     _write(IODIRA, direction); 
+}
+
+void MCP23S17::directionB(char direction) {
+     _write(IODIRB, direction); 
+}
+
+void MCP23S17::outputA(char byte) {
+    _write(OLATA, byte); 
+}
+
+void MCP23S17::outputB(char byte) {
+    _write(OLATB, byte); 
+}
+
+char MCP23S17::inputA() {
+    return _read(GPIOA);
+}
+
+char MCP23S17::inputB() {
+    return _read(GPIOB);
+}
+