AnyWire

Arduino abstraction layer to support both Wire and SoftwareWire.

Included in this repo are a local copy of SoftwareWire and a forked copy of HTU2xD_SHT2x_Si70xx, which has been modified to support AnyWire.

See the included demo.ino, which reads from both hardware and software I2C sensors ("GY-21" breakout boards).

// an SHT21 sensor using hardware I2C:
HTU2xD_SHT2x_SI70xx hw_sht21(HTU2xD_SENSOR, HUMD_12BIT_TEMP_14BIT);

// an SHT21 sensor using software I2C:
uint8_t sw_sda_pin = 12;
uint8_t sw_scl_pin = 11;
SoftwareWire swire(sw_sda_pin, sw_scl_pin);
HTU2xD_SHT2x_SI70xx sw_sht21(HTU2xD_SENSOR, HUMD_12BIT_TEMP_14BIT, &swire);

Caveats

Not all of the Wire API is supported by SoftwareWire. For the unsupported portions, AnyWire simply enters into an infinite loop:

bool AnyWire::getWireTimeoutFlag(void) {
  if (_softwareWire) {
    while (1) { __asm volatile(""); } // not supported
  } else {
    return Wire.getWireTimeoutFlag();
  }
}

These include:

• begin() when called with an address
• setWireTimeout() when called with reset_with_timeout = true
• getWireTimeoutFlag()
• clearWireTimeoutFlag()
• requestFrom() when called with a second "internal" address and size
• flush()

License

AnyWire.h, AnyWire.cpp and demo.ino are copyright 2022 Jason Pepas, released under the terms of the MIT License. See https://opensource.org/licenses/MIT.

SoftwareWire.h and SoftwareWire.cpp are copied from https://github.com/Testato/SoftwareWire, which is GPL-3.0 licensed.

HTU2xD_SHT2x_Si70xx.h and HTU2xD_SHT2x_Si70xx.cpp are forked from https://github.com/enjoyneering/HTU2xD_SHT2x_Si70xx, which is GPL-3.0 licensed.