v 0.4
Dependents:
MCP23S17Test
MCP23S17_Basic_IO_Demo
HelloWorld
Lab3-SnakeGame
... more
MCP23S17.cpp@7:53498e24592c, 2010-08-22 (annotated)
- Committer:
- romilly
- Date:
- Sun Aug 22 15:37:25 2010 +0000
- Revision:
- 7:53498e24592c
- Parent:
-
6:7b5e59c0e71c
- Child:
- 8:841b19734955
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
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| romilly |
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/* MCP23S17 - drive the Microchip MCP23S17 16-bit Port Extender using SPI
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| romilly |
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* Copyright (c) 2010 Romilly Cocking
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* Released under the MIT License: http://mbed.org/license/mit
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*
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* version 0.2
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*/
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#include "mbed.h"
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#include "MCP23S17.h"
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MCP23S17::MCP23S17(SPI& spi, PinName ncs, char writeOpcode) : _spi(spi), _ncs(ncs) {
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_writeOpcode = writeOpcode;
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_readOpcode = _writeOpcode | 1; // low order bit = 1 for read
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_init();
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}
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char MCP23S17::_read(char address) {
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_ncs = 0;
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_spi.write(_readOpcode);
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_spi.write(address);
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char result = _spi.write(0);
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_ncs = 1;
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return result;
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}
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void MCP23S17::_write(char address, char data) {
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_ncs = 0;
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_spi.write(_writeOpcode);
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_spi.write(address);
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_spi.write(data);
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_ncs = 1;
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}
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void MCP23S17::_init() {
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_write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers
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}
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void MCP23S17::directionA(char direction) {
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_write(IODIRA, direction);
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}
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void MCP23S17::directionB(char direction) {
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_write(IODIRB, direction);
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}
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void MCP23S17::interruptEnableA(char interruptsEnabledMask) {
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_write(GPINTENA, interruptsEnabledMask);
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}
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void MCP23S17::interruptEnableB(char interruptsEnabledMask) {
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_write(GPINTENB, interruptsEnabledMask);
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}
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void MCP23S17::mirrorInterrupts(bool mirror) {
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char iocon = _read(IOCON);
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if (mirror) {
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iocon = iocon | INTERRUPT_MIRROR_BIT;
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} else {
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iocon = iocon & ~INTERRUPT_MIRROR_BIT;
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}
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_write(IOCON, iocon);
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}
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void MCP23S17::interruptPolarity(Polarity polarity) {
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char iocon = _read(IOCON);
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if (polarity == ACTIVE_LOW) {
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iocon = iocon & ~INTERRUPT_POLARITY_BIT;
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} else {
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iocon = iocon | INTERRUPT_POLARITY_BIT;
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}
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_write(IOCON, iocon);
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}
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void MCP23S17::defaultValueA(char valuesToCompare) {
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_write(DEFVALA, valuesToCompare);
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}
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void MCP23S17::interruptControlA(char interruptContolBits) {
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_write(INTCONA, interruptContolBits);
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}
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void MCP23S17::outputA(char byte) {
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_write(OLATA, byte);
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}
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void MCP23S17::outputB(char byte) {
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_write(OLATB, byte);
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}
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char MCP23S17::inputA() {
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return _read(GPIOA);
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}
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char MCP23S17::inputB() {
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return _read(GPIOB);
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}
|
Romilly Cocking
MCP23S17 I/O Expander