I2C 8+8 expander with extra features

[aratti]

Ioannis , I have more than 20 automations working with I2C installed in different places and all works pretty well. If you want give a try do it, providing that you optoisolate the digital part (inputs & outputs) from the external power devices (motor; valves; relays and sensors of any type).

Al.

[Ioannis]

Thanks for the reply.

I have some projects where the inputs are optoisolated, outputs are relays and analog drive directly the PIC inputs through some sort of zener diode protection.

For the digital part I use the Parallel input-Serial Output and the reverse, Serial Input-Parallel Output registers like the 4021 and 4094 or the A6841/MIC6841 that drives relays directly. Especially the latter is a good IC and drives relays with no need for other components. I wonder if there is an equivalent in I2C.

This registers need at least 5 lines for data-in, data-out, clock, strobe and load. That is why I think to jump into I2C.

Regards,
Ioannis