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());
-        
-    }
-}