GY-63_MS5611/libraries/TCA9555

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.