Hi everyone, Miguel brought me here :) Thanks for everyone's help and sorry if this message doesn't turn up in the proper thread or if the quotes are messed up since I'm not used to mailing lists.
On Mon, Jul 28, 2014 at 9:13 AM, Miguel Garcia <gacuest at gmail.com http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook> wrote:
Peter Green is right. We need 6 ADCs.
2014-07-27 17:06 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook>:
but you should be able to do keyboard matrix scanning to cover 16 buttons, 4 input 4 output... unless you really really want all possible button combinations, hmmm...
are there any keys which may not be pressed together, so you can do matrix-scanning on those, at least?
Matrix-scanning is not a good idea. We want all possible button combinations.
thought so
ok so you have an IC for the GPIO, and one for the ADC.
We could use two different IC's, but wouldn't using an appropriate microcontroller be a less complex solution? That would probably make the schematics and PCB easier to design, although having to develop the software for the uc is a big con. Plus those I2C expansion chips look pretty neat.
Some uc's in the ATtiny48 family have 6 ADCs and enough I/O pins. Also, while we're only considering what we need for user input, there may be other needs I don't know about (an extra ADC for battery monitoring? I have no idea). That would be a point in favor of using a uc.