Diff: user_interface/MCP23017.cpp

Revision:

0:371773dd3dd1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/user_interface/MCP23017.cpp	Wed May 04 15:41:13 2011 +0000
@@ -0,0 +1,179 @@
+/* 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 Initial Release
+* version 0.3 Cleaned up
+*/
+
+#include "mbed.h"
+#include "MCP23017.h"
+
+DigitalOut Busy(LED4);
+
+/** Create an MCP23017 object connected to the specified I2C object and using the specified deviceAddress
+*
+* @param I2C &i2c the I2C port to connect to
+* @param char deviceAddress the address of the MSC23017
+*/
+MCP23017::MCP23017(I2C &i2c, char deviceAddress) : _i2c(i2c) {
+printf("creating mcp23017\n");
+    _writeOpcode = deviceAddress & 0xFE; // low order bit = 0 for write
+    _readOpcode  = deviceAddress | 0x01; // low order bit = 1 for read
+    busy = false;
+    posted = false;
+    _init();
+    readW(INTFA);
+    readW(GPIOA);
+printf("mcp23017 created\n");
+}
+
+/** Read from specified MCP23017 register
+*
+* @param char address the internal registeraddress of the MSC23017
+* @returns data from register
+*/
+short MCP23017::_read(char address) {//blocks on busy and still waits for completion
+    char data[2];
+    i2c_status s;
+    data[0] = address;
+    do {
+        s = _read(address, data, 1);
+    } while (s == i2c_busy);
+    return (s == i2c_ok) ? data[0] : -2;
+}
+
+MCP23017::i2c_status MCP23017::_read(char reg, char *data, int size) {//returns on busy but still waits for completion
+    if (testbusy()) return i2c_busy;
+    _i2c.write(_writeOpcode, &reg, 1, true); //in a future version of the i2c lib write should return a status like ACK or NACK or busy
+    int result = _i2c.read(_readOpcode, data, size);
+    releasebusy();
+    return result ? i2c_nack : i2c_ok;
+}
+
+int MCP23017::readW(char address) {//blocks on busy and still waits for completion
+    char data[2];
+    i2c_status s;
+    data[0] = address;
+    do {
+        s = _read(address, data, 2);
+    } while (s == i2c_busy);
+    return (s == i2c_ok) ? *(unsigned short*)data : -1;
+}
+
+
+/** Write to specified MCP23017 register
+*
+* @param char address the internal registeraddress of the MSC23017
+*/
+void MCP23017::_write(char address, char byte) {//blocks on busy and still waits for completion
+    i2c_status s;
+    char data[2];
+    data[0] = address;
+    data[1] = byte;
+    do {
+        s = _write(data, 2);
+    } while (s == i2c_busy);
+//    _i2c.write(_writeOpcode, data, 2);    // Write data to selected Register
+    return ; //s; //in the future return the status
+}
+
+MCP23017::i2c_status MCP23017::_write(char *data, int size, bool rpt) {//returns on busy but still waits for completion
+    if (testbusy()) return i2c_busy;
+    int result = 0;
+    _i2c.write(_writeOpcode, data, size, rpt);    // Write data to selected Register
+    releasebusy();
+    return result ? i2c_nack : i2c_ok;
+}
+
+/** Init MCP23017
+*
+* @param
+* @returns
+*/
+void MCP23017::_init() {
+    _write(IOCON, (IOCON_BYTE_MODE | IOCON_ODR )); // Open drain interrupt, operations toggle between A and B registers
+
+}
+
+/** Set I/O direction of specified MCP23017 Port
+*
+* @param Port Port address (Port_A or Port_B)
+* @param char direction pin direction (0 = output, 1 = input)
+*/
+void MCP23017::direction(Port port, char direction) {
+    _write(port + IODIRA, direction);
+}
+
+/** Set Pull-Up Resistors on specified MCP23017 Port
+*
+* @param Port Port address (Port_A or Port_B)
+* @param char offOrOn per pin (0 = off, 1 = on)
+*/
+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);
+}
+
+/** Write to specified MCP23017 Port
+*
+* @param Port Port address (Port_A or Port_B)
+* @param char byte data to write
+*/
+void MCP23017::write(Port port, char byte) {
+    _write(port + OLATA, byte);
+}
+
+/** Read from specified MCP23017 Port
+*
+* @param Port Port address (Port_A or Port_B)
+* @returns data from Port
+*/
+char MCP23017::read(Port port) {
+    return _read(port + GPIOA);
+}
+
+void MCP23017::write(Port port, const char *buffer, int len, bool rpt) {
+    len++;
+    char *data = new char[len];
+    data[0] = port+OLATA;
+    i2c_status s;
+    for (int k=1; k< len; k++) data[k] = buffer[k-1];
+    do {
+      s = _write(data, len, rpt);//toggle A and B, start with port
+    } while (s == i2c_busy);
+    delete[] data;
+}
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