Diff: MCP23017.cpp

Revision:

0:1a9288cc0630

Child:

1:e2edbd61f4d0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP23017.cpp	Sat Dec 18 18:49:19 2010 +0000
@@ -0,0 +1,132 @@
+/* MCP23017 - drive the Microchip MCP23017 16-bit Port Extender using I2C
+* Copyright (c) 2010 Wim Huiskamp, Romilly Cocking (original version for SPI)
+*
+* Released under the MIT License: http://mbed.org/license/mit
+*
+* version 0.2
+*/
+
+#include "mbed.h"
+#include "MCP23017.h"
+
+MCP23017::MCP23017(I2C &i2c, char deviceAddress) : _i2c(i2c) {
+    _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
+    _readOpcode  = deviceAddress | 0x01; // low order bit = 1 for read
+    _init();
+}
+
+char MCP23017::_read(char address) {
+    char data[2];
+    char result;
+
+    data[0] = address;
+    _i2c.write(_writeOpcode, data, 1);      // Select Register for reading
+    result = _i2c.read(_readOpcode);        // Read from selected Register
+    
+    return result;
+}
+
+
+void MCP23017::_write(char address, char byte) {
+    char data[2];
+
+    data[0] = address;
+    data[1] = byte;
+    _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register
+}
+
+
+void MCP23017::_init() {
+    _write(IOCON, (IOCON_BYTE_MODE | IOCON_HAEN )); // Hardware addressing on, operations toggle between A and B registers
+
+}
+
+void MCP23017::direction(Port port, char direction) {
+    _write(port + IODIRA, direction);
+}
+
+void MCP23017::configurePullUps(Port port, char offOrOn) {
+    _write(port + GPPUA, offOrOn);
+}
+
+void MCP23017::interruptEnable(Port port, char interruptsEnabledMask) {
+    _write(port + GPINTENA, interruptsEnabledMask);
+}
+
+void MCP23017::mirrorInterrupts(bool mirror) {
+ char iocon = _read(IOCON);
+    if (mirror) {
+        iocon = iocon | INTERRUPT_MIRROR_BIT;
+    } else {
+        iocon = iocon & ~INTERRUPT_MIRROR_BIT;
+    }
+    _write(IOCON, iocon);
+
+}
+
+void  MCP23017::interruptPolarity(Polarity polarity) {
+    char iocon = _read(IOCON);
+    if (polarity == ACTIVE_LOW) {
+        iocon = iocon & ~INTERRUPT_POLARITY_BIT;
+    } else {
+        iocon = iocon | INTERRUPT_POLARITY_BIT;
+    }
+    _write(IOCON, iocon);
+}
+
+void MCP23017::defaultValue(Port port, char valuesToCompare) {
+    _write(port + DEFVALA, valuesToCompare);
+}
+
+void MCP23017::interruptControl(Port port, char interruptControlBits) {
+    _write(port + INTCONA, interruptControlBits);
+}
+
+void MCP23017::write(Port port, char byte) {
+    _write(port + OLATA, byte);
+    
+//faster    (56 sec for lcd init)
+//   char data[2];
+//
+//   data[0] = OLATA + port;
+//   data[1] = byte;
+//   _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register
+
+//faster  47 sec for complete init
+//   _i2c.start();
+//   _i2c.write(_writeOpcode);    // Select Device
+//   _i2c.write(OLATA + port);    // Select Register
+//   _i2c.write(byte);            // Write data to selected Register
+//   _i2c.stop();  
+}
+    
+
+char MCP23017::read(Port port) {
+    return _read(port + GPIOA);
+}
+
+// Optimised Databus write operation for Graphics LCD.
+//   Port A is used as databus, Port B is used as controlbus.
+//
+void MCP23017::databus_write(char data, char ctrl_1, char ctrl_2, char ctrl_3, char ctrl_4) {
+
+   _i2c.start();
+   _i2c.write(_writeOpcode);    // Select Device
+   _i2c.write(OLATA);           // Select Register A
+
+//Remove separate CS Low, to speed up
+//   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
+//   _i2c.write(ctrl_1);          // Write control to Port B  and Auto-incr to Register A
+   
+   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
+   _i2c.write(ctrl_2);          // Write control to Port B  and Auto-incr to Register A
+   
+   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
+   _i2c.write(ctrl_3);          // Write control to Port B  and Auto-incr to Register A
+
+//Remove separate CS High, to speed up
+//   _i2c.write(data);            // Write data to Port A Register and Auto-incr to Register B
+//   _i2c.write(ctrl_4);          // Write control to Port B  and Auto-incr to Register A
+   
+   _i2c.stop();  
+}
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