mirror of
https://github.com/RobTillaart/Arduino.git
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156 lines
3.3 KiB
C++
156 lines
3.3 KiB
C++
//
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// FILE: MCP23017.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.1.0
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// PURPOSE: library for MCP23017 I2C module
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// LICENSE: MIT
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// HISTORY:
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// 2019-10-12: 0.1.0 initial version
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//
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// TODO:
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// interrupts
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// caching for performance?
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// INPUT_PULLUP
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//
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#include "MCP23017.h"
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#define MCP23017_DDR_A 0x00 // Data Direction Register
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#define MCP23017_DDR_B 0x01
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#define MCP23017_PUR_A 0x0C // Pull Up Resistors
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#define MCP23017_PUR_B 0x0D
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#define MCP23017_IOCR 0x0A // IO control register
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#define MCP23017_GPIOA 0x12
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#define MCP23017_GPIOB 0x13
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MCP23017::MCP23017(uint8_t addr)
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{
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_addr = addr;
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}
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#if defined(ESP8266) || defined(ESP32)
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void MCP23017::begin(const uint8_t dataPin, const uint8_t clockPin)
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{
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Wire.begin(dataPin, clockPin);
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// Force IPUT_PULLUP
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writeReg(MCP23017_PUR_A, 0xFF);
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writeReg(MCP23017_PUR_B, 0xFF);
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}
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#endif
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void MCP23017::begin()
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{
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Wire.begin();
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// Force IPUT_PULLUP
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writeReg(MCP23017_IOCR, 0b00100000); // disable addres increment (datasheet)
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writeReg(MCP23017_PUR_A, 0xFF);
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writeReg(MCP23017_PUR_B, 0xFF);
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}
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// single pin interface
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// pin 0..15
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// value INPUT, OUTPUT, INPUT_PULLUP
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// TODO: split INPUT_PULLUP and INPUT, for now they are the same
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void MCP23017::pinMode(uint8_t pin, uint8_t value)
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{
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if (pin > 15) return;
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if (value != INPUT && value != INPUT_PULLUP && value != OUTPUT) return;
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uint8_t DDR = MCP23017_DDR_A; // Data Direction Register
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if (pin > 7)
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{
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DDR = MCP23017_DDR_B;
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pin -= 8;
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}
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uint8_t val = readReg(DDR);
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uint8_t mask = 1 << pin;
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// only work with valid
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if (value == INPUT || value == INPUT_PULLUP)
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{
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val |= mask;
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}
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else if (value == OUTPUT)
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{
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val &= ~mask;
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}
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// other values won't change val ....
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writeReg(DDR, val);
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}
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void MCP23017::digitalWrite(uint8_t pin, uint8_t value) // pin = 0..15
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{
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if (pin > 15) return;
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uint8_t IOR = MCP23017_GPIOA;
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if (pin > 7)
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{
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IOR = MCP23017_GPIOB;
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pin -= 8;
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}
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uint8_t val = readReg(IOR);
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uint8_t mask = 1 << pin;
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if (value) val |= mask;
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else val &= ~mask;
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writeReg(IOR, val);
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}
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uint8_t MCP23017::digitalRead(uint8_t pin)
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{
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if (pin > 15) return -100; // TODO magic number
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uint8_t IOR = MCP23017_GPIOA;
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if (pin > 7)
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{
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IOR = MCP23017_GPIOB;
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pin -= 8;
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}
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uint8_t val = readReg(IOR);
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uint8_t mask = 1 << pin;
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if (val & mask) return HIGH;
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return LOW;
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}
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// 8 pins interface
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// whole register at once
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void MCP23017::pinMode8(uint8_t port, uint8_t value)
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{
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if (port == 0) writeReg(MCP23017_DDR_A, value);
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if (port == 1) writeReg(MCP23017_DDR_B, value);
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// explicitely ignore other values.
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}
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void MCP23017::write8(uint8_t port, uint8_t value) // port = 0..1
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{
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if (port == 0) writeReg(MCP23017_GPIOA, value);
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if (port == 1) writeReg(MCP23017_GPIOB, value);
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// explicitely ignore other values.
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}
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int MCP23017::read8(uint8_t port)
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{
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if (port == 0) return readReg(MCP23017_GPIOA);
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if (port == 1) return readReg(MCP23017_GPIOB);
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return -100; // TODO magic number
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}
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void MCP23017::writeReg(uint8_t reg, uint8_t value)
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{
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Wire.beginTransmission(_addr);
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Wire.write(reg);
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Wire.write(value);
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Wire.endTransmission();
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}
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uint8_t MCP23017::readReg(uint8_t reg)
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{
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Wire.beginTransmission(_addr);
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Wire.write(reg);
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Wire.endTransmission();
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Wire.requestFrom(_addr, (uint8_t)1);
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return Wire.read();
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}
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// -- END OF FILE --
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