Pca95x4 - I2C GPIO Expander

Summary

The PCA95x4 provides 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus applications.

Device Family

NXP

PCA9534: https://www.nxp.com/docs/en/data-sheet/PCA9534.pdf
PCA9534A: https://www.nxp.com/docs/en/data-sheet/PCA9534.pdf
PCA9554/PCA9554A: https://www.nxp.com/docs/en/data-sheet/PCA9554_9554A.pdf

Texas Instruments

PCA9534: http://www.ti.com/lit/ds/symlink/pca9534.pdf
PCA9534A: http://www.ti.com/lit/ds/symlink/pca9534a.pdf
PCA9554: http://www.ti.com/lit/ds/symlink/pca9554.pdf
PCA9554A: http://www.ti.com/lit/ds/symlink/pca9554a.pdf

Binding Notes

PCA9534/PCA9554 and PCA9534A/PCA9554A are identical except for a few differences.

The removal of the internal I/O pull-up resistor which greatly reduces power consumption when the I/Os are held LOW.
Each has a fixed I2C address. This allows for up to 16 of these devices (8 of each) on the same I2C bus.

References

http://ecee.colorado.edu/~mcclurel/Philips_I2C_IO_Expanders_AN469_2.pdf