Daniel Wyatt
A library for the Microchip MCP23008 I2C 8-bit I/O expander.
MCP23008.cpp@0:4f712bd739d0, 2012-06-15 (annotated)
- Committer:
- dewyatt
- Date:
- Fri Jun 15 03:31:48 2012 +0000
- Revision:
- 0:4f712bd739d0
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| dewyatt | 0:4f712bd739d0 | 1 | #include "MCP23008.hpp" |
| dewyatt | 0:4f712bd739d0 | 2 | |
| dewyatt | 0:4f712bd739d0 | 3 | namespace { |
| dewyatt | 0:4f712bd739d0 | 4 | const uint8_t MCP23008_ADDRESS = 0x40; |
| dewyatt | 0:4f712bd739d0 | 5 | |
| dewyatt | 0:4f712bd739d0 | 6 | /* MCP23008 registers */ |
| dewyatt | 0:4f712bd739d0 | 7 | const uint8_t IODIR = 0x00; |
| dewyatt | 0:4f712bd739d0 | 8 | const uint8_t IPOL = 0x01; |
| dewyatt | 0:4f712bd739d0 | 9 | const uint8_t GPINTEN = 0x02; |
| dewyatt | 0:4f712bd739d0 | 10 | const uint8_t DEFVAL = 0x03; |
| dewyatt | 0:4f712bd739d0 | 11 | const uint8_t INTCON = 0x04; |
| dewyatt | 0:4f712bd739d0 | 12 | const uint8_t IOCON = 0x05; |
| dewyatt | 0:4f712bd739d0 | 13 | const uint8_t GPPU = 0x06; |
| dewyatt | 0:4f712bd739d0 | 14 | const uint8_t INTF = 0x07; |
| dewyatt | 0:4f712bd739d0 | 15 | const uint8_t INTCAP = 0x08; |
| dewyatt | 0:4f712bd739d0 | 16 | const uint8_t GPIO = 0x09; |
| dewyatt | 0:4f712bd739d0 | 17 | const uint8_t OLAT = 0x0A; |
| dewyatt | 0:4f712bd739d0 | 18 | }; |
| dewyatt | 0:4f712bd739d0 | 19 | |
| dewyatt | 0:4f712bd739d0 | 20 | MCP23008::MCP23008 ( PinName sda, PinName scl, uint8_t address, Frequency freq ) |
| dewyatt | 0:4f712bd739d0 | 21 | : i2c ( sda, scl ), |
| dewyatt | 0:4f712bd739d0 | 22 | i2c_address ( MCP23008_ADDRESS | address ) { |
| dewyatt | 0:4f712bd739d0 | 23 | if ( address > 7 ) |
| dewyatt | 0:4f712bd739d0 | 24 | error ( "MCP23008::MCP23008: address is out of range, must be <= 7\n" ); |
| dewyatt | 0:4f712bd739d0 | 25 | |
| dewyatt | 0:4f712bd739d0 | 26 | i2c.frequency ( ( int ) freq ); |
| dewyatt | 0:4f712bd739d0 | 27 | reset (); |
| dewyatt | 0:4f712bd739d0 | 28 | } |
| dewyatt | 0:4f712bd739d0 | 29 | |
| dewyatt | 0:4f712bd739d0 | 30 | void MCP23008::set_input_pins ( uint8_t pins ) { |
| dewyatt | 0:4f712bd739d0 | 31 | uint8_t value = read_register ( IODIR ); |
| dewyatt | 0:4f712bd739d0 | 32 | write_register ( IODIR, value | pins ); |
| dewyatt | 0:4f712bd739d0 | 33 | } |
| dewyatt | 0:4f712bd739d0 | 34 | |
| dewyatt | 0:4f712bd739d0 | 35 | void MCP23008::set_output_pins ( uint8_t pins ) { |
| dewyatt | 0:4f712bd739d0 | 36 | uint8_t value = read_register ( IODIR ); |
| dewyatt | 0:4f712bd739d0 | 37 | write_register ( IODIR, value & ~pins ); |
| dewyatt | 0:4f712bd739d0 | 38 | } |
| dewyatt | 0:4f712bd739d0 | 39 | |
| dewyatt | 0:4f712bd739d0 | 40 | void MCP23008::write_outputs ( uint8_t values ) { |
| dewyatt | 0:4f712bd739d0 | 41 | write_register ( GPIO, values ); |
| dewyatt | 0:4f712bd739d0 | 42 | } |
| dewyatt | 0:4f712bd739d0 | 43 | |
| dewyatt | 0:4f712bd739d0 | 44 | uint8_t MCP23008::read_outputs () { |
| dewyatt | 0:4f712bd739d0 | 45 | return read_register ( OLAT ); |
| dewyatt | 0:4f712bd739d0 | 46 | } |
| dewyatt | 0:4f712bd739d0 | 47 | |
| dewyatt | 0:4f712bd739d0 | 48 | uint8_t MCP23008::read_inputs () { |
| dewyatt | 0:4f712bd739d0 | 49 | return read_register ( GPIO ); |
| dewyatt | 0:4f712bd739d0 | 50 | } |
| dewyatt | 0:4f712bd739d0 | 51 | |
| dewyatt | 0:4f712bd739d0 | 52 | void MCP23008::set_input_polarity ( uint8_t values ) { |
| dewyatt | 0:4f712bd739d0 | 53 | write_register ( IPOL, values ); |
| dewyatt | 0:4f712bd739d0 | 54 | } |
| dewyatt | 0:4f712bd739d0 | 55 | |
| dewyatt | 0:4f712bd739d0 | 56 | uint8_t MCP23008::get_input_polarity () { |
| dewyatt | 0:4f712bd739d0 | 57 | return read_register ( IPOL ); |
| dewyatt | 0:4f712bd739d0 | 58 | } |
| dewyatt | 0:4f712bd739d0 | 59 | |
| dewyatt | 0:4f712bd739d0 | 60 | void MCP23008::set_pullups ( uint8_t values ) { |
| dewyatt | 0:4f712bd739d0 | 61 | write_register ( GPPU, values ); |
| dewyatt | 0:4f712bd739d0 | 62 | } |
| dewyatt | 0:4f712bd739d0 | 63 | |
| dewyatt | 0:4f712bd739d0 | 64 | uint8_t MCP23008::get_pullups () { |
| dewyatt | 0:4f712bd739d0 | 65 | return read_register ( GPPU ); |
| dewyatt | 0:4f712bd739d0 | 66 | } |
| dewyatt | 0:4f712bd739d0 | 67 | |
| dewyatt | 0:4f712bd739d0 | 68 | void MCP23008::interrupt_on_changes ( uint8_t pins ) { |
| dewyatt | 0:4f712bd739d0 | 69 | uint8_t value = read_register ( INTCON ); |
| dewyatt | 0:4f712bd739d0 | 70 | value &= ~pins; |
| dewyatt | 0:4f712bd739d0 | 71 | write_register ( INTCON, value ); |
| dewyatt | 0:4f712bd739d0 | 72 | value = read_register ( GPINTEN ); |
| dewyatt | 0:4f712bd739d0 | 73 | value |= pins; |
| dewyatt | 0:4f712bd739d0 | 74 | write_register ( GPINTEN, value ); |
| dewyatt | 0:4f712bd739d0 | 75 | } |
| dewyatt | 0:4f712bd739d0 | 76 | |
| dewyatt | 0:4f712bd739d0 | 77 | void MCP23008::disable_interrupts ( uint8_t pins ) { |
| dewyatt | 0:4f712bd739d0 | 78 | uint8_t value = read_register ( GPINTEN ); |
| dewyatt | 0:4f712bd739d0 | 79 | value &= ~pins; |
| dewyatt | 0:4f712bd739d0 | 80 | write_register ( GPINTEN, value ); |
| dewyatt | 0:4f712bd739d0 | 81 | } |
| dewyatt | 0:4f712bd739d0 | 82 | |
| dewyatt | 0:4f712bd739d0 | 83 | void MCP23008::acknowledge_interrupt ( uint8_t &pin, uint8_t &values ) { |
| dewyatt | 0:4f712bd739d0 | 84 | pin = read_register ( INTF ); |
| dewyatt | 0:4f712bd739d0 | 85 | values = read_register ( INTCAP ); |
| dewyatt | 0:4f712bd739d0 | 86 | } |
| dewyatt | 0:4f712bd739d0 | 87 | |
| dewyatt | 0:4f712bd739d0 | 88 | uint8_t MCP23008::read_register ( uint8_t reg ) { |
| dewyatt | 0:4f712bd739d0 | 89 | char data[] = {reg}; |
| dewyatt | 0:4f712bd739d0 | 90 | if ( 0 != i2c.write ( i2c_address, data, 1 ) ) |
| dewyatt | 0:4f712bd739d0 | 91 | error ( "MCP23008::read_register: Missing ACK for write\n" ); |
| dewyatt | 0:4f712bd739d0 | 92 | |
| dewyatt | 0:4f712bd739d0 | 93 | if ( 0 != i2c.read ( i2c_address, data, 1 ) ) |
| dewyatt | 0:4f712bd739d0 | 94 | error ( "MCP23008:read_register: Missing ACK for read\n" ); |
| dewyatt | 0:4f712bd739d0 | 95 | |
| dewyatt | 0:4f712bd739d0 | 96 | return data[0]; |
| dewyatt | 0:4f712bd739d0 | 97 | } |
| dewyatt | 0:4f712bd739d0 | 98 | |
| dewyatt | 0:4f712bd739d0 | 99 | void MCP23008::write_register ( uint8_t reg, uint8_t value ) { |
| dewyatt | 0:4f712bd739d0 | 100 | char data[] = {reg, value}; |
| dewyatt | 0:4f712bd739d0 | 101 | if ( 0 != i2c.write ( i2c_address, data, 2 ) ) |
| dewyatt | 0:4f712bd739d0 | 102 | error ( "MCP23008::write_register: Missing ACK for write\n" ); |
| dewyatt | 0:4f712bd739d0 | 103 | } |
| dewyatt | 0:4f712bd739d0 | 104 | |
| dewyatt | 0:4f712bd739d0 | 105 | void MCP23008::write_mask ( uint8_t reg, uint8_t mask, bool value ) { |
| dewyatt | 0:4f712bd739d0 | 106 | uint8_t val; |
| dewyatt | 0:4f712bd739d0 | 107 | val = read_register ( reg ); |
| dewyatt | 0:4f712bd739d0 | 108 | if ( value ) |
| dewyatt | 0:4f712bd739d0 | 109 | val |= mask; |
| dewyatt | 0:4f712bd739d0 | 110 | else |
| dewyatt | 0:4f712bd739d0 | 111 | val &= ~mask; |
| dewyatt | 0:4f712bd739d0 | 112 | |
| dewyatt | 0:4f712bd739d0 | 113 | write_register ( reg, val ); |
| dewyatt | 0:4f712bd739d0 | 114 | } |
| dewyatt | 0:4f712bd739d0 | 115 | |
| dewyatt | 0:4f712bd739d0 | 116 | void MCP23008::reset ( ) { |
| dewyatt | 0:4f712bd739d0 | 117 | write_register ( IODIR, 0xFF ); |
| dewyatt | 0:4f712bd739d0 | 118 | for ( uint8_t reg = IPOL; reg <= OLAT; reg++ ) |
| dewyatt | 0:4f712bd739d0 | 119 | write_register ( reg, 0 ); |
| dewyatt | 0:4f712bd739d0 | 120 | } |