Embedded Files
Source code of dondo_MCP23017.cpp library (~/libraries/dondo_MCP23017_i2c2/dondo_MCP23017.cpp)
/***************************************************
This is a library for the MCP23017 i2c port expander
These displays use I2C to communicate, 2 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
/****************************************************
Modified by Sirio Maccolini 2018
****************************************************/
#ifdef __AVR
#include <avr/pgmspace.h>
#elif defined(ESP8266)
#include <pgmspace.h>
#endif
#include "dondo_MCP23017.h"
#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
// minihelper to keep Arduino backward compatibility
static inline void wiresend(uint8_t x) {
#if ARDUINO >= 100
Wire1.write((uint8_t) x);
#else
Wire1.send(x);
#endif
}
static inline uint8_t wirerecv(void) {
#if ARDUINO >= 100
return Wire1.read();
#else
return Wire1.receive();
#endif
}
/**
* Bit number associated to a give Pin
*/
uint8_t dondo_MCP23017::bitForPin(uint8_t pin){
return pin%8;
}
/**
* Register address, port dependent, for a given PIN
*/
uint8_t dondo_MCP23017::regForPin(uint8_t pin, uint8_t portAaddr, uint8_t portBaddr){
return(pin<8) ?portAaddr:portBaddr;
}
/**
* Reads a given register
*/
uint8_t dondo_MCP23017::readRegister(uint8_t addr){
// read the current GPINTEN
Wire1.beginTransmission(MCP23017_ADDRESS | i2caddr);
wiresend(addr);
Wire1.endTransmission();
Wire1.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
return wirerecv();
}
/**
* Writes a given register
*/
void dondo_MCP23017::writeRegister(uint8_t regAddr, uint8_t regValue){
// Write the register
Wire1.beginTransmission(MCP23017_ADDRESS | i2caddr);
wiresend(regAddr);
wiresend(regValue);
Wire1.endTransmission();
}
/**
* Helper to update a single bit of an A/B register.
* - Reads the current register value
* - Writes the new register value
*/
void dondo_MCP23017::updateRegisterBit(uint8_t pin, uint8_t pValue, uint8_t portAaddr, uint8_t portBaddr) {
uint8_t regValue;
uint8_t regAddr=regForPin(pin,portAaddr,portBaddr);
uint8_t bit=bitForPin(pin);
regValue = readRegister(regAddr);
// set the value for the particular bit
bitWrite(regValue,bit,pValue);
writeRegister(regAddr,regValue);
}
////////////////////////////////////////////////////////////////////////////////
/**
* Initializes the MCP23017 given its HW selected address, see datasheet for Address selection.
*/
void dondo_MCP23017::begin(uint8_t addr) {
if (addr > 7) {
addr = 7;
}
i2caddr = addr;
Wire1.begin();
// set defaults!
// all inputs on port A and B
writeRegister(MCP23017_IODIRA,0xff);
writeRegister(MCP23017_IODIRB,0xff);
}
/**
* Initializes the default MCP23017, with 000 for the configurable part of the address
*/
void dondo_MCP23017::begin(void) {
begin(0);
}
/**
* Sets the pin mode to either INPUT or OUTPUT
*/
void dondo_MCP23017::pinMode(uint8_t p, uint8_t d) {
updateRegisterBit(p,(d==INPUT),MCP23017_IODIRA,MCP23017_IODIRB);
}
/**
* Reads all 16 pins (port A and B) into a single 16 bits variable.
*/
uint16_t dondo_MCP23017::readGPIOAB() {
uint16_t ba = 0;
uint8_t a;
// read the current GPIO output latches
Wire1.beginTransmission(MCP23017_ADDRESS | i2caddr);
wiresend(MCP23017_GPIOA);
Wire1.endTransmission();
Wire1.requestFrom(MCP23017_ADDRESS | i2caddr, 2);
a = wirerecv();
ba = wirerecv();
ba <<= 8;
ba |= a;
return ba;
}
/**
* Read a single port, A or B, and return its current 8 bit value.
* Parameter b should be 0 for GPIOA, and 1 for GPIOB.
*/
uint8_t dondo_MCP23017::readGPIO(uint8_t b) {
// read the current GPIO output latches
Wire1.beginTransmission(MCP23017_ADDRESS | i2caddr);
if (b == 0)
wiresend(MCP23017_GPIOA);
else {
wiresend(MCP23017_GPIOB);
}
Wire1.endTransmission();
Wire1.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
return wirerecv();
}
/**
* Writes all the pins in one go. This method is very useful if you are implementing a multiplexed matrix and want to get a decent refresh rate.
*/
void dondo_MCP23017::writeGPIOAB(uint16_t ba) {
Wire1.beginTransmission(MCP23017_ADDRESS | i2caddr);
wiresend(MCP23017_GPIOA);
wiresend(ba & 0xFF);
wiresend(ba >> 8);
Wire1.endTransmission();
}
void dondo_MCP23017::digitalWrite(uint8_t pin, uint8_t d) {
uint8_t gpio;
uint8_t bit=bitForPin(pin);
// read the current GPIO output latches
uint8_t regAddr=regForPin(pin,MCP23017_OLATA,MCP23017_OLATB);
gpio = readRegister(regAddr);
// set the pin and direction
bitWrite(gpio,bit,d);
// write the new GPIO
regAddr=regForPin(pin,MCP23017_GPIOA,MCP23017_GPIOB);
writeRegister(regAddr,gpio);
}
void dondo_MCP23017::pullUp(uint8_t p, uint8_t d) {
updateRegisterBit(p,d,MCP23017_GPPUA,MCP23017_GPPUB);
}
uint8_t dondo_MCP23017::digitalRead(uint8_t pin) {
uint8_t bit=bitForPin(pin);
uint8_t regAddr=regForPin(pin,MCP23017_GPIOA,MCP23017_GPIOB);
return (readRegister(regAddr) >> bit) & 0x1;
}
/**
* Configures the interrupt system. both port A and B are assigned the same configuration.
* Mirroring will OR both INTA and INTB pins.
* Opendrain will set the INT pin to value or open drain.
* polarity will set LOW or HIGH on interrupt.
* Default values after Power On Reset are: (false,flase, LOW)
* If you are connecting the INTA/B pin to arduino 2/3, you should configure the interupt handling as FALLING with
* the default configuration.
*/
void dondo_MCP23017::setupInterrupts(uint8_t mirroring, uint8_t openDrain, uint8_t polarity){
// configure the port A
uint8_t ioconfValue=readRegister(MCP23017_IOCONA);
bitWrite(ioconfValue,6,mirroring);
bitWrite(ioconfValue,2,openDrain);
bitWrite(ioconfValue,1,polarity);
writeRegister(MCP23017_IOCONA,ioconfValue);
// Configure the port B
ioconfValue=readRegister(MCP23017_IOCONB);
bitWrite(ioconfValue,6,mirroring);
bitWrite(ioconfValue,2,openDrain);
bitWrite(ioconfValue,1,polarity);
writeRegister(MCP23017_IOCONB,ioconfValue);
}
/**
* Set's up a pin for interrupt. uses arduino MODEs: CHANGE, FALLING, RISING.
*
* Note that the interrupt condition finishes when you read the information about the port / value
* that caused the interrupt or you read the port itself. Check the datasheet can be confusing.
*
*/
void dondo_MCP23017::setupInterruptPin(uint8_t pin, uint8_t mode) {
// set the pin interrupt control (0 means change, 1 means compare against given value);
updateRegisterBit(pin,(mode!=CHANGE),MCP23017_INTCONA,MCP23017_INTCONB);
// if the mode is not CHANGE, we need to set up a default value, different value triggers interrupt
// In a RISING interrupt the default value is 0, interrupt is triggered when the pin goes to 1.
// In a FALLING interrupt the default value is 1, interrupt is triggered when pin goes to 0.
updateRegisterBit(pin,(mode==FALLING),MCP23017_DEFVALA,MCP23017_DEFVALB);
// enable the pin for interrupt
updateRegisterBit(pin,HIGH,MCP23017_GPINTENA,MCP23017_GPINTENB);
}
uint8_t dondo_MCP23017::getLastInterruptPin(){
uint8_t intf;
// try port A
intf=readRegister(MCP23017_INTFA);
for(int i=0;i<8;i++) if (bitRead(intf,i)) return i;
// try port B
intf=readRegister(MCP23017_INTFB);
for(int i=0;i<8;i++) if (bitRead(intf,i)) return i+8;
return MCP23017_INT_ERR;
}
uint8_t dondo_MCP23017::getLastInterruptPinValue(){
uint8_t intPin=getLastInterruptPin();
if(intPin!=MCP23017_INT_ERR){
uint8_t intcapreg=regForPin(intPin,MCP23017_INTCAPA,MCP23017_INTCAPB);
uint8_t bit=bitForPin(intPin);
return (readRegister(intcapreg)>>bit) & (0x01);
}
return MCP23017_INT_ERR;
}
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