Romilly Cocking / MCP23S17

v 0.4

Dependents:   MCP23S17Test MCP23S17_Basic_IO_Demo HelloWorld Lab3-SnakeGame ... more

MCP23S17.cpp@9:068b1e8909bb, 2010-08-28 (annotated)

Committer:
romilly
Date:
Sat Aug 28 09:48:38 2010 +0000
Revision:
9:068b1e8909bb
Parent:
8:841b19734955 
Added pull=up configuration

Who changed what in which revision?

UserRevisionLine numberNew contents of line
romilly 7:53498e24592c 1 /* MCP23S17 - drive the Microchip MCP23S17 16-bit Port Extender using SPI
romilly 7:53498e24592c 2 * Copyright (c) 2010 Romilly Cocking
romilly 7:53498e24592c 3 * Released under the MIT License: http://mbed.org/license/mit
romilly 7:53498e24592c 4 *
romilly 9:068b1e8909bb 5 * version 0.4
romilly 7:53498e24592c 6 */
romilly 7:53498e24592c 7
romilly 7:53498e24592c 8 #include "mbed.h"
romilly 7:53498e24592c 9 #include "MCP23S17.h"
romilly 7:53498e24592c 10
romilly 7:53498e24592c 11 MCP23S17::MCP23S17(SPI& spi, PinName ncs, char writeOpcode) : _spi(spi), _ncs(ncs) {
romilly 7:53498e24592c 12 _writeOpcode = writeOpcode;
romilly 7:53498e24592c 13 _readOpcode = _writeOpcode | 1; // low order bit = 1 for read
romilly 7:53498e24592c 14 _init();
romilly 7:53498e24592c 15 }
romilly 7:53498e24592c 16
romilly 7:53498e24592c 17 char MCP23S17::_read(char address) {
romilly 7:53498e24592c 18 _ncs = 0;
romilly 7:53498e24592c 19 _spi.write(_readOpcode);
romilly 7:53498e24592c 20 _spi.write(address);
romilly 7:53498e24592c 21 char result = _spi.write(0);
romilly 7:53498e24592c 22 _ncs = 1;
romilly 7:53498e24592c 23 return result;
romilly 7:53498e24592c 24 }
romilly 7:53498e24592c 25
romilly 8:841b19734955 26 char MCP23S17::_read(Port port, char address) {
romilly 8:841b19734955 27 return _read(address + (char) port);
romilly 8:841b19734955 28 }
romilly 8:841b19734955 29
romilly 7:53498e24592c 30 void MCP23S17::_write(char address, char data) {
romilly 7:53498e24592c 31 _ncs = 0;
romilly 7:53498e24592c 32 _spi.write(_writeOpcode);
romilly 7:53498e24592c 33 _spi.write(address);
romilly 7:53498e24592c 34 _spi.write(data);
romilly 7:53498e24592c 35 _ncs = 1;
romilly 7:53498e24592c 36 }
romilly 7:53498e24592c 37
romilly 8:841b19734955 38 void MCP23S17::_write(Port port, char address, char data) {
romilly 8:841b19734955 39 _write(address + (char) port, data);
romilly 8:841b19734955 40 }
romilly 8:841b19734955 41
romilly 7:53498e24592c 42 void MCP23S17::_init() {
romilly 7:53498e24592c 43 _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers
romilly 7:53498e24592c 44 }
romilly 7:53498e24592c 45
romilly 8:841b19734955 46 void MCP23S17::direction(Port port, char direction) {
romilly 8:841b19734955 47 _write(port, IODIRA, direction);
romilly 7:53498e24592c 48 }
romilly 7:53498e24592c 49
romilly 9:068b1e8909bb 50 void MCP23S17::configurePullUps(Port port, char offOrOn) {
romilly 9:068b1e8909bb 51 _write(port, GPPUA, offOrOn);
romilly 9:068b1e8909bb 52 }
romilly 7:53498e24592c 53
romilly 8:841b19734955 54 void MCP23S17::interruptEnable(Port port, char interruptsEnabledMask) {
romilly 8:841b19734955 55 _write(port, GPINTENA, interruptsEnabledMask);
romilly 7:53498e24592c 56 }
romilly 7:53498e24592c 57
romilly 7:53498e24592c 58 void MCP23S17::mirrorInterrupts(bool mirror) {
romilly 7:53498e24592c 59 char iocon = _read(IOCON);
romilly 7:53498e24592c 60 if (mirror) {
romilly 7:53498e24592c 61 iocon = iocon | INTERRUPT_MIRROR_BIT;
romilly 7:53498e24592c 62 } else {
romilly 7:53498e24592c 63 iocon = iocon & ~INTERRUPT_MIRROR_BIT;
romilly 7:53498e24592c 64 }
romilly 7:53498e24592c 65 _write(IOCON, iocon);
romilly 7:53498e24592c 66
romilly 7:53498e24592c 67 }
romilly 7:53498e24592c 68
romilly 7:53498e24592c 69 void MCP23S17::interruptPolarity(Polarity polarity) {
romilly 7:53498e24592c 70 char iocon = _read(IOCON);
romilly 7:53498e24592c 71 if (polarity == ACTIVE_LOW) {
romilly 7:53498e24592c 72 iocon = iocon & ~INTERRUPT_POLARITY_BIT;
romilly 7:53498e24592c 73 } else {
romilly 7:53498e24592c 74 iocon = iocon | INTERRUPT_POLARITY_BIT;
romilly 7:53498e24592c 75 }
romilly 7:53498e24592c 76 _write(IOCON, iocon);
romilly 7:53498e24592c 77 }
romilly 7:53498e24592c 78
romilly 8:841b19734955 79 void MCP23S17::defaultValue(Port port, char valuesToCompare) {
romilly 8:841b19734955 80 _write(port, DEFVALA, valuesToCompare);
romilly 7:53498e24592c 81 }
romilly 7:53498e24592c 82
romilly 8:841b19734955 83 void MCP23S17::interruptControl(Port port, char interruptContolBits) {
romilly 8:841b19734955 84 _write(port, INTCONA, interruptContolBits);
romilly 7:53498e24592c 85 }
romilly 7:53498e24592c 86
romilly 8:841b19734955 87 void MCP23S17::write(Port port, char byte) {
romilly 8:841b19734955 88 _write(port, OLATA, byte);
romilly 7:53498e24592c 89 }
romilly 7:53498e24592c 90
romilly 8:841b19734955 91 char MCP23S17::read(Port port) {
romilly 8:841b19734955 92 return _read(port, GPIOA);
romilly 7:53498e24592c 93 }
romilly 7:53498e24592c 94