v 0.4
Dependents: MCP23S17Test MCP23S17_Basic_IO_Demo HelloWorld Lab3-SnakeGame ... more
Revision 2:6144709f1700, committed 2010-08-21
- Comitter:
- romilly
- Date:
- Sat Aug 21 14:46:59 2010 +0000
- Parent:
- 1:5abd129839e7
- Child:
- 3:089a2a754567
- Commit message:
Changed in this revision
--- /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); +} +
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MCP23S17.h Sat Aug 21 14:46:59 2010 +0000 @@ -0,0 +1,47 @@ +/* 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" + +#ifndef SER23K256_H +#define SER23K256_H + +// all register addresses assume IOVCON.BANK = 0 (POR default) + +#define IODIRA 0x00 +#define IODIRB 0x01 +#define IOCON 0x0A +#define GPIOA 0x12 +#define GPIOB 0x13 +#define OLATA 0x14 +#define OLATB 0x15 + +// Control settings + +#define IOCON_BANK 0x80 // Banked registers +#define IOCON_BYTE_MODE 0x20 // Disables sequential operation. If bank = 0, operations toggle between A and B registers +#define IOCON_HAEN 0x08 // Hardware address enable + +class MCP23S17 { +public: + MCP23S17(SPI& spi, PinName ncs, char writeOpcode); + void directionA(char direction); + void directionB(char direction); + char inputA(); + char inputB(); + void outputA(char byte); + void outputB(char byte); +protected: + SPI& _spi; + DigitalOut _ncs; + void _init(); + void _write(char address, char data); + char _read(char address); + char _readOpcode; + char _writeOpcode; +}; + +#endif \ No newline at end of file
--- a/main.cpp Sat Aug 21 07:05:21 2010 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,88 +0,0 @@ -#include "mbed.h" - -/* -* next baby step towards towards a library for MCP23S17 -* I'm proposing to allow 8-bit and 16-bit conditioning, reads, and writes -* and interrupt conditioning -* -* Unless someone asks for them, I'm not going to implement -* multi-reads or writes where a sequence of many bytes are read from or written -* to the same register -* -* This is currently experimental code. I'm still checking that I've understood the chip API. -*/ - - -// all register addresses assume IOVCON.BANK = 0 (POR default) - -#define IODIRA 0x00 -#define IODIRB 0x01 -#define IOCON 0x0A -#define GPIOA 0x12 -#define GPIOB 0x13 -#define OLATA 0x14 -#define OLATB 0x15 - -// Control settings - -#define IOCON_BANK 0x80 // Banked registers -#define IOCON_BYTE_MODE 0x20 // Disables sequential operation. If bank = 0, operations toggle between A and B registers -#define IOCON_HAEN 0x08 // Hardware address enable - -SPI spi(p5, p6, p7); -DigitalOut ncs(p20); // not chip select; bring this low to enable the chip -char writeOpcode = 0x40; // A0, A1, A2 are tied to ground on the breadboard. -char readOpcode = writeOpcode | 1; // low order bit = 1 for read - -void _write(char address, char data) { - ncs = 0; - spi.write(writeOpcode); - spi.write(address); - spi.write(data); - ncs = 1; -} - -char _read(char address) { - ncs = 0; - spi.write(readOpcode); - spi.write(address); - char result = spi.write(0); - ncs = 1; - return result; -} - -void init() { - _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers -} - -void directionA(char direction) { - _write(IODIRA, direction); -} - -void directionB(char direction) { - _write(IODIRB, direction); -} - -void outputA(char byte) { - _write(OLATA, byte); -} - -void outputB(char byte) { - _write(OLATB, byte); -} - -char inputA() { - return _read(GPIOA); -} - -int main() { - init(); - directionA(0xFF); // all 8 bits set to input - directionB(0x00); // all 8 bits set to ouptut - while(1) { - wait(0.2); - // copy inputs from A to outputs on B - outputB(inputA()); - - } -}