Diff: MCP23017.cpp

Revision:

0:a6a5d942b58f

Child:

2:2a17f52c550a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP23017.cpp	Sun Nov 28 20:41:49 2010 +0000
@@ -0,0 +1,243 @@
+/*  MCP23017 library for Arduino
+    Copyright (C) 2009 David Pye    <davidmpye@gmail.com
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "MCP23017.h"
+#include "mbed.h"
+
+union {
+    uint8_t  value8[2];
+    uint16_t value16;
+} tmp_data;
+
+using namespace mbed;
+/*
+ *
+ */
+MCP23017::MCP23017(PinName sda, PinName scl, int i2cAddress)  : _i2c(sda, scl) {
+    MCP23017_i2cAddress = i2cAddress;
+    reset();                                  // initialise chip to power-on condition
+}
+
+/*******************************************************************************
+ * reset
+ * Set configuration (IOCON) and direction(IODIR) registers to initial state
+ */
+void MCP23017::reset() {
+//
+// First make sure that the device is in BANK=0 mode
+//
+    writeRegister(0x05, (unsigned char)0x00);
+//
+// set direction registers to inputs
+//
+    writeRegister(IODIR, (unsigned short)0xFFFF);
+//
+// set all other registers to zero (last od 10 registers is OLAT)
+//
+    for (int reg_addr = 2 ; reg_addr <= OLAT ; reg_addr+=2) {
+        writeRegister(reg_addr, (unsigned short)0x0000);
+    }
+//
+// Set the shadow registers to power-on state
+//
+    shadow_IODIR = 0xFFFF;
+    shadow_GPIO  = 0;
+    shadow_GPPU  = 0;
+    shadow_IPOL  = 0;
+}
+
+/*******************************************************************************
+ * pinMode
+ */
+void MCP23017::pinMode(int pin, int mode) {
+    if (DIR_INPUT) {
+        shadow_IODIR |= 1 << pin;
+    } else {
+        shadow_IODIR &= ~(1 << pin);
+    }
+    writeRegister(IODIR, (unsigned short)shadow_IODIR);
+}
+
+/*******************************************************************************
+ * digitalRead
+ */
+int MCP23017::digitalRead(int pin) {
+    shadow_GPIO = readRegister(GPIO);
+    if ( shadow_GPIO & (1 << pin)) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+/*******************************************************************************
+ * write_bit
+ * Write a 1/0 to a single bit of the 16-bit port
+ */
+void MCP23017::write_bit(int value, int bit_number) {
+    if (value == 0) {
+        shadow_GPIO &= ~(1 << bit_number);
+    } else {
+        shadow_GPIO |= 1 << bit_number;
+    }
+    writeRegister(GPIO, (unsigned short)shadow_GPIO);
+}
+
+/*******************************************************************************
+ * Write a combination of bits to the 16-bit port
+ */
+void MCP23017::write_mask(unsigned short data, unsigned short mask) {
+    shadow_GPIO = (shadow_GPIO & ~mask) | data;
+    writeRegister(GPIO, (unsigned short)shadow_GPIO);
+}
+
+/*******************************************************************************
+ * read_bit
+ * Read a single bit from the 16-bit port
+ */
+int  MCP23017::read_bit(int bit_number) {
+    shadow_GPIO = readRegister(GPIO);
+    return  ((shadow_GPIO >> bit_number) & 0x0001);
+}
+
+/*******************************************************************************
+ * read_mask
+ */
+int  MCP23017::read_mask(unsigned short mask) {
+    shadow_GPIO = readRegister(GPIO);
+    return (shadow_GPIO & mask);
+}
+
+/*******************************************************************************
+ * Config
+ * set direction and pull-up registers
+ */
+void MCP23017::config(unsigned short dir_config, unsigned short pullup_config,  unsigned short polarity_config) {
+    shadow_IODIR = dir_config;
+    writeRegister(IODIR, (unsigned short)shadow_IODIR);
+    shadow_GPPU = pullup_config;
+    writeRegister(GPPU, (unsigned short)shadow_GPPU);
+    shadow_IPOL = polarity_config;
+    writeRegister(IPOL, (unsigned short)shadow_IPOL);
+}
+
+/*******************************************************************************
+ * digitalWrite
+ */
+void MCP23017::digitalWrite(int pin, int val) {
+    //If this pin is an INPUT pin, a write here will
+    //enable the internal pullup
+    //otherwise, it will set the OUTPUT voltage
+    //as appropriate.
+    bool isOutput = !(shadow_IODIR & 1<<pin);
+
+    if (isOutput) {
+        //This is an output pin so just write the value
+        if (val) shadow_GPIO |= 1 << pin;
+        else shadow_GPIO &= ~(1 << pin);
+        writeRegister(GPIO, (unsigned short)shadow_GPIO);
+    } else {
+        //This is an input pin, so we need to enable the pullup
+        if (val) {
+            shadow_GPPU |= 1 << pin;
+        } else {
+            shadow_GPPU &= ~(1 << pin);
+        }
+        writeRegister(GPPU, (unsigned short)shadow_GPPU);
+    }
+}
+
+/*******************************************************************************
+ * digitalWordRead
+ */
+unsigned short MCP23017::digitalWordRead() {
+    shadow_GPIO = readRegister(GPIO);
+    return shadow_GPIO;
+}
+
+/*******************************************************************************
+ * digitalWordWrite
+ */
+void MCP23017::digitalWordWrite(unsigned short w) {
+    shadow_GPIO = w;
+    writeRegister(GPIO, (unsigned short)shadow_GPIO);
+}
+
+/*******************************************************************************
+ * inputPolarityMask
+ */
+void MCP23017::inputPolarityMask(unsigned short mask) {
+    writeRegister(IPOL, mask);
+}
+
+/*******************************************************************************
+ * inputoutputMask
+ */
+void MCP23017::inputOutputMask(unsigned short mask) {
+    shadow_IODIR = mask;
+    writeRegister(IODIR, (unsigned short)shadow_IODIR);
+}
+
+/*******************************************************************************
+ * internalPullupMask
+ */
+void MCP23017::internalPullupMask(unsigned short mask) {
+    shadow_GPPU = mask;
+    writeRegister(GPPU, (unsigned short)shadow_GPPU);
+}
+
+
+
+//PRIVATE
+/*******************************************************************************
+ * writeRegister
+ * write a byte
+ */
+void MCP23017::writeRegister(int regAddress, unsigned char data) {
+    char  buffer[2];
+
+    buffer[0] = regAddress;
+    buffer[1] = data;
+    _i2c.write(MCP23017_i2cAddress, buffer, 2);
+}
+
+/*******************************************************************************
+ * writeRegister
+ * write two bytes
+ */
+void MCP23017::writeRegister(int regAddress, unsigned short data) {
+    char  buffer[3];
+
+    buffer[0] = regAddress;
+    tmp_data.value16 = data;
+    buffer[1] = tmp_data.value8[0];
+    buffer[2] = tmp_data.value8[1];
+
+    _i2c.write(MCP23017_i2cAddress, buffer, 3);
+}
+
+/*******************************************************************************
+ * readRegister
+ */
+int MCP23017::readRegister(int regAddress) {
+    char buffer[2];
+
+    buffer[0] = regAddress;
+    _i2c.write(MCP23017_i2cAddress, buffer, 1);
+    _i2c.read(MCP23017_i2cAddress, buffer, 2);
+
+    return ((int)(buffer[0] + (buffer[1]<<8)));
+}