[FTC]: Custom I2C IO expander allowed connected to CDIM?

[Mike002]

So if our team builds a custom IO expander (PCF8574) to connect to the CDIM on I2C buss is this allowed? 8 additional digital inputs/outputs gained very simply.

[Billfred]

Originally Posted by Mike002

So if our team builds a custom IO expander (PCF8574) to connect to the CDIM on I2C buss is this allowed? 8 additional digital inputs/outputs gained very simply.

RE11 and RE17 govern this, and connecting to the I2C bus sounds promising, but I don't know enough of your application to say anything with certainty. This would be worth an official Q&A.

That said, what on earth are you doing that one Core Device Interface Module (let alone that RE07 lets you use two) isn't enough?!

[Mike002]

Thanks for the reply and I know it is over the top a bit but in all of this I was hoping to take the students into a bit of electronics. Building and applying a digital interface like this would open the creativity door to a whole new world.
I think First is missing the boat on this by not allowing things like custom circuits and small embedded micros in addition to the android control interfaces. Let's start them young!