Diff: MCP23008.cpp

Revision:

0:4f712bd739d0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MCP23008.cpp	Fri Jun 15 03:31:48 2012 +0000
@@ -0,0 +1,120 @@
+#include "MCP23008.hpp"
+
+namespace {
+const uint8_t MCP23008_ADDRESS  = 0x40;
+
+/* MCP23008 registers */
+const uint8_t IODIR             = 0x00;
+const uint8_t IPOL              = 0x01;
+const uint8_t GPINTEN           = 0x02;
+const uint8_t DEFVAL            = 0x03;
+const uint8_t INTCON            = 0x04;
+const uint8_t IOCON             = 0x05;
+const uint8_t GPPU              = 0x06;
+const uint8_t INTF              = 0x07;
+const uint8_t INTCAP            = 0x08;
+const uint8_t GPIO              = 0x09;
+const uint8_t OLAT              = 0x0A;
+};
+
+MCP23008::MCP23008 ( PinName sda, PinName scl, uint8_t address, Frequency freq )
+        : i2c ( sda, scl ),
+        i2c_address ( MCP23008_ADDRESS | address ) {
+    if ( address > 7 )
+        error ( "MCP23008::MCP23008: address is out of range, must be <= 7\n" );
+
+    i2c.frequency ( ( int ) freq );
+    reset ();
+}
+
+void MCP23008::set_input_pins ( uint8_t pins ) {
+    uint8_t value = read_register ( IODIR );
+    write_register ( IODIR, value | pins );
+}
+
+void MCP23008::set_output_pins ( uint8_t pins ) {
+    uint8_t value = read_register ( IODIR );
+    write_register ( IODIR, value & ~pins );
+}
+
+void MCP23008::write_outputs ( uint8_t values ) {
+    write_register ( GPIO, values );
+}
+
+uint8_t MCP23008::read_outputs () {
+    return read_register ( OLAT );
+}
+
+uint8_t MCP23008::read_inputs () {
+    return read_register ( GPIO );
+}
+
+void MCP23008::set_input_polarity ( uint8_t values ) {
+    write_register ( IPOL, values );
+}
+
+uint8_t MCP23008::get_input_polarity () {
+    return read_register ( IPOL );
+}
+
+void MCP23008::set_pullups ( uint8_t values ) {
+    write_register ( GPPU, values );
+}
+
+uint8_t MCP23008::get_pullups () {
+    return read_register ( GPPU );
+}
+
+void MCP23008::interrupt_on_changes ( uint8_t pins ) {
+    uint8_t value = read_register ( INTCON );
+    value &= ~pins;
+    write_register ( INTCON, value );
+    value = read_register ( GPINTEN );
+    value |= pins;
+    write_register ( GPINTEN, value );
+}
+
+void MCP23008::disable_interrupts ( uint8_t pins ) {
+    uint8_t value = read_register ( GPINTEN );
+    value &= ~pins;
+    write_register ( GPINTEN, value );
+}
+
+void MCP23008::acknowledge_interrupt ( uint8_t &pin, uint8_t &values ) {
+    pin = read_register ( INTF );
+    values = read_register ( INTCAP );
+}
+
+uint8_t MCP23008::read_register ( uint8_t reg ) {
+    char data[] = {reg};
+    if ( 0 != i2c.write ( i2c_address, data, 1 ) )
+        error ( "MCP23008::read_register: Missing ACK for write\n" );
+
+    if ( 0 != i2c.read ( i2c_address, data, 1 ) )
+        error ( "MCP23008:read_register: Missing ACK for read\n" );
+
+    return data[0];
+}
+
+void MCP23008::write_register ( uint8_t reg, uint8_t value ) {
+    char data[] = {reg, value};
+    if ( 0 != i2c.write ( i2c_address, data, 2 ) )
+        error ( "MCP23008::write_register: Missing ACK for write\n" );
+}
+
+void MCP23008::write_mask ( uint8_t reg, uint8_t mask, bool value ) {
+    uint8_t val;
+    val = read_register ( reg );
+    if ( value )
+        val |= mask;
+    else
+        val &= ~mask;
+
+    write_register ( reg, val );
+}
+
+void MCP23008::reset ( ) {
+    write_register ( IODIR, 0xFF );
+    for ( uint8_t reg = IPOL; reg <= OLAT; reg++ )
+        write_register ( reg, 0 );
+}