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3.5 KiB
3.5 KiB
MCP23008
Arduino library for MCP23008 8 channel I2C port expander.
Description
This library gives easy control over the 8 pins of a (I2C) MCP23008 chip.
This IC is strongly related tot the MCP23017 I2C port expander - https://github.com/RobTillaart/MCP23017_RT Programming Interface is kept the same as much as possible.
Since 0.1.1 the digitalWrite(pin, value) is optimized. If a pin is not changed it will not be written again to save time.
Interface
Constructor
- MCP23008(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..7, mode = INPUT, OUTPUT. Returns true if successful.
- bool digitalWrite(uint8_t pin, uint8_t value) pin = 0..7, value = LOW(0) HIGH (!0). Returns true if successful.
- uint8_t digitalRead(uint8_t pin) pin = 0..7, returns LOW or HIGH, might set the lastError();
- bool setPolarity(uint8_t pin, bool reversed) pin = 0..7, set reversed flag. Returns true if successful.
- bool getPolarity(uint8_t pin, bool &reversed) pin = 0..7, reads reversed flag. Returns true if successful.
- bool setPullup(uint8_t pin, bool pullup) pin = 0..7, set pull-up flag. Returns true if successful.
- bool getPullup(uint8_t pin, bool &pullup) pin = 0..7, reads pull-up flag. Returns true if successful.
8 pins interface
- bool pinMode8(uint8_t value) value = 0..255. Returns true if successful.
- bool write8(uint8_t value) value = 0..255. Returns true if successful.
- uint8_t read8() reads 8 pins into one byte.
- bool setPolarity8(uint8_t mask) sets polarity for 8 channels at once. Returns true if successful.
- bool getPolarity8(uint8_t &mask) reads polarity of 8 channels at once. Returns true if successful.
- bool setPullup8(uint8_t mask) sets pull-up for 8 channels at once. Returns true if successful.
- bool getPullup8(uint8_t &mask) reads pull-up for 8 channels at once. Returns true if successful.
Error codes
If one of the above functions return false, there might be an error.
- int lastError() Above functions set an error flag that can be read with this function.
Reading it will reset the flag to MCP23008_OK.
| DESCRIPTION | VALUE |
|---|---|
| MCP23008_OK | 0x00 |
| MCP23008_PIN_ERROR | 0x81 |
| MCP23008_I2C_ERROR | 0x82 |
| MCP23008_VALUE_ERROR | 0x83 |
| MCP23008_PORT_ERROR | 0x84 |
Operation
See examples.
Future
- keep in sync with MCP23017