Id really appreciate some input on this one...(sorry, no pun intended)
I'm planning a project which in reality needs to be a large pin matrix, so a large number of inputs, a large number of outputs and then the ability to determine which output is connected to which input.
Its like a big cable harness tester i suppose but I'm not worried about multiple pins being shorted, it would only ever be one output connected to one input.
So, I've been looking at the NXP PCA9698 ic's as they offer a load of IO and lots of available addresses on on one i2C bus.
The only thing I'm concerned about is resources, I haven't got a great deal of experience with handling lots of IO - so for example, if I wanted to test 240 x 240 pins, I'd need 12 of these ICs, so far so good - the datasheet says that 64 address are available for this chip.
I'm thinking the programme would work in very simplistic terms by holding the first output to a know state (high), and then scan all the inputs to see which one is also high, and then do the same with the second, output etc etc.
Am I likely to run into any issues with this just in the way of time it takes to query all the I/O or with the amount of available memory to process/store all these states? I've been using the 16Mhz Pro Mini's (ATMega328P).
Also, can anyone tell me if the wire.h library supports this chip?
Thanks for reading,