GY-63_MS5611/libraries/MCP23017_RT/README.md
2022-01-09 20:53:12 +01:00

4.2 KiB

Arduino CI Arduino-lint JSON check License: MIT GitHub release

MCP23017_RT

Arduino library for MCP23017 16 channel I2C port expander.

Description

This library gives easy control over the 16 pins of a (I2C) MCP23017 chip.

This IC is strongly related tot the MCP23S17 SPI port expander - https://github.com/RobTillaart/MCP23S17 Programming Interface is kept the same as much as possible.

Interface

Constructor

  • MCP23017(uint8_t address, TwoWire *wire = &Wire) constructor, with default Wire interface.
    Can be overruled with Wire0..WireN.
  • bool begin() for UNO, returns true if successful.
  • bool begin(uint8_t sda, uint8_t scl) for ESP32, returns true if successful.
  • bool isConnected() returns true if connected, false otherwise.

Single pin interface

  • bool pinMode(uint8_t pin, uint8_t mode) pin = 0..15, mode = INPUT, OUTPUT, returns true if successful.
  • bool digitalWrite(uint8_t pin, uint8_t value) pin = 0..15, value = LOW(0) HIGH (!0), returns true if successful.
  • uint8_t digitalRead(uint8_t pin) pin = 0..15, returns LOW or HIGH, might set the lastError();
  • bool setPolarity(uint8_t pin, bool reversed) pin = 0..15, set reversed flag, returns true if successful.
  • bool getPolarity(uint8_t pin, bool &reversed) pin = 0..15, reads reversed flag, returns true if successful.
  • bool setPullup(uint8_t pin, bool pullup) pin = 0..15, set pull-up flag, returns true if successful.
  • bool getPullup(uint8_t pin, bool &pullup) pin = 0..15, reads pull-up flag, returns true if successful.

8 pins interface

  • bool pinMode8(uint8_t port, uint8_t value) port = 0..1, value = 0..255, returns true if successful.
  • bool write8(uint8_t port, uint8_t value) port = 0..1, value = 0..255, returns true if successful.
  • uint8_t read8(uint8_t port) port = 0..1, reads 8 pins into one byte.
  • bool setPolarity8(uint8_t port, uint8_t mask) port = 0..1, sets polarity for 8 channels at once.
  • bool getPolarity8(uint8_t port, uint8_t &mask) port = 0..1, reads polarity of 8 channels at once.
  • bool setPullup8(uint8_t port, uint8_t mask) port = 0..1, sets pull-up for 8 channels at once.
  • bool getPullup8(uint8_t port, uint8_t &mask) port = 0..1, reads pull-up for 8 channels at once.

16 pins interface

  • bool pinMode16(uint16_t value) value = 0..0xFFFF, returns true if successful.
  • bool write16(uint16_t value) value = 0..0xFFFF, returns true if successful.
  • uint16_t read16() reads 16 pins into an uint16_t.
  • bool setPolarity16(uint16_t mask) sets polarity for 16 channels.
  • bool getPolarity16(uint16_t &mask) reads polarity of 16 channels.
  • bool setPullup16(uint16_t mask) sets pull-up for 16 channels.
  • bool getPullup16(uint16_t &mask) reads pull-up for 16 channels.

Error codes

  • int lastError() Above functions set an error flag that can be read with this function.
    Reading it will reset the flag to MCP23017_OK.
DESCRIPTION VALUE
MCP23017_OK 0x00
MCP23017_PIN_ERROR 0x81
MCP23017_I2C_ERROR 0x82
MCP23017_VALUE_ERROR 0x83
MCP23017_PORT_ERROR 0x84

Operation

See examples.

Future

Must

  • Improve and extend documentation
  • add examples

Should

  • extend error codes
  • optimize code - squeeze footprint
  • optimize code - do not write if pin does not chance (~25%)

Could

  • initial value (16 bit?) as begin parameter (breaking change)
    • depends on input output pull-up etc?
  • investigate auto address increment?