[Arm-netbook] IC for analog and digital buttons (EOMA-68)

[Luke Kenneth Casson Leighton]

On Sun, Jul 27, 2014 at 1:04 PM, Miguel Garcia <gacuest at gmail.com> wrote:
> We are designing a handheld-game console (based on EOMA-68).

 great!

> The problem is that EOMA-68 has very few GPIO.

 ah - it now has quite a few: 17 at the last count, however yes they
are all multiplexed.

> We have 17 digital buttons, 2 analog joystick (
> http://www.digikey.com/product-detail/en/254TA103B50B/254TA103B50B-ND/1755918
> ) and 2 analog triggers (
> http://www.digikey.com/product-detail/en/EVA-W7NR04B34/P13569-ND/1135944
> ).
>
> Luke will use on the tablet the next IC: PCA9536.

 yep.  it is a low-cost I2C 8-bit GPIO

> However, this component does not meet our requirements.

 no ADC...

> Does anyone know a IC that meets these requirements (at least 17
> digital buttons and at least 4 ADCs)?

 that's quite a lot!

 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?

 i will see if there is an I2C ADC/GPIO IC around... also now SPI is
available so you could use that.

l.