PCA9555 I2C to 16 line controller board
IC2 is a synchronous bidirectional communication
system that allows devices to transfer data using
only two wires: a bidirectional data line (SDA) and a clock line (SCL). Max clock rate is 400kHz.
The PCA9555 chip is a
I2C to 16 I/0 line decoder which can control an alternative
BPF or any
other device you want to add that needs switching control.
This board contains a
PCA9555 and two ULN2803A 8bit darlington driver
It is single sided (only two topside links) and it is designed for home- etching.
Layout and etching masks are provided here.
For and explanation of I2C and the TrxAVR I2C addressing options see TrxAVR-Picastar I2C interface
For a description Hobcat/TrxAVR soft-key control of this board, see PCA9555 button control
Layout and schematic of the card are below.
There are only two tracks in the underside so ignore the bottomcopper and etch as single sided.
PCA9555_bottomcopper.pdf (not needed - build single sided)
TrxAVR-Picastar home page