GY-63_MS5611/libraries/TCA9555/README.md
2021-12-28 18:38:10 +01:00

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TCA9555

Arduino library for TCA9555 16 channel I2C port expander.

Description

This library gives easy control over the 16 pins of a TCA9555 chip.

The TCA9555 supports up to 400 kHz I2C.

TCA9535

from datasheet:

The TCA9535 is identical to the TCA9555, except that the TCA9535 does not include the internal I/O pull-up resistor, which requires pull-ups and pull-downs on unused I/O pins when configured as an input and not driven. This reduces power consumption when the I/O is held low.

There is a TCA9535 class which is a (convenience) wrapper around the TCA9555 class. This allows one to create TCA9535 objects.

Interface

Check the datasheet for details

Constructor

  • TCA9555(uint8_t address, TwoWire *wire = &Wire) constructor, with default Wire interface. Can be overruled with Wire0..WireN.

  • TCA9535(uint8_t address, TwoWire *wire = &Wire) idem.

  • 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.

1 pin interface

  • bool pinMode(uint8_t pin, uint8_t mode) idem.
  • 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 the value of the pin HIGH or LOW.
  • bool setPolarity(uint8_t pin, uint8_t value) inverts polarity of an INPUT pin.
  • uint8_t getPolarity(uint8_t pin) returns 1 if a pin is inverted.

8 pin interface

port = 0..1
mask = 0..255

  • bool pinMode8(uint8_t port, uint8_t mask) set the mode of eight pins in one call.
  • bool write8(uint8_t port, uint8_t mask) returns true if successful. Especially useful if one needs to trigger multiple pins at the exact same time.
  • uint8_t read8(uint8_t port) returns a bit pattern for pins 0..7 or pins 8..15.
  • bool setPolarity8(uint8_t port, uint8_t mask) inverts polarity of the 8 INPUT pins in one action.
  • uint8_t getPolarity(uint8_t port) returns a mask with a 1 for every INPUT pin that is inverted.

16 pin interface

Be aware that the 16 pins interface does two calls to the 8 pins interface. So it is impossible to switch pins from the 2 groups of 8 at exactly the same time without additional hardware.

  • bool pinMode16(uint16_t mask) set the mode of sixteen pins in one call.
  • bool write16(uint16_t mask) mask = 0x0000 .. 0xFFFF, returns true if successful.
  • uint16_t read16() Returns a bit pattern for pins 0..15.
  • bool setPolarity16(uint16_t mask) inverts polarity of the 8 INPUT pins in one action. Returns true upon success.
  • uint16_t getPolarity() returns a mask of 16 bits with a 1 for every INPUT pin that is inverted.

Error codes

  • int lastError() Above functions set an error flag that can be read with this function. Reading it will reset the flag to TCA9555_OK.
DESCRIPTION VALUE
TCA9555_OK 0x00
TCA9555_PIN_ERROR 0x81
TCA9555_I2C_ERROR 0x82
TCA9555_VALUE_ERROR 0x83
TCA9555_PORT_ERROR 0x84
TCA9555_INVALID_READ -100

Operation

See examples

Future

Must

  • test all functionality (initial version is written with no hardware around)
  • add TCA9535 error codes

Could

  • buy TCA9555 / TCA9535
  • rethink class hierarchy?
  • investigate internal pull up etc.