Diff: MCP23017.cpp
- Revision:
- 0:d76c38ee24ab
diff -r 000000000000 -r d76c38ee24ab MCP23017.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP23017.cpp Fri Apr 13 17:44:17 2012 +0000
@@ -0,0 +1,242 @@
+/* MCP23017 library for Arduino
+ Copyright (C) 2009 David Pye <davidmpye@gmail.com
+ Modified for use on the MBED ARM platform
+
+ 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;
+
+/*-----------------------------------------------------------------------------
+ *
+ */
+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 of 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;
+}
+
+/*-----------------------------------------------------------------------------
+ * 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);
+}
+
+/*-----------------------------------------------------------------------------
+ * 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);
+}
+
+/*----------------------------------------------------------------------------
+ * write Register
+ * 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)));
+}
+
+/*-----------------------------------------------------------------------------
+ * 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;
+ }
+}
+
+/*-----------------------------------------------------------------------------
+ * 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);
+}
+