-da
On Mon, Dec 9, 2013 at 2:23 PM, joem joem@martindale-electric.co.uk wrote:
How best to get touch working on EOMA?
you mean EOMA68?
almost most all capacitive panels are I2C. goodix ICs or futuretech (e.g. FT5306). these are already fully supported under linux: drivers are easy to find and many of them are already in the sunxi 3.4 kernel tree. i had to do a bit of searching for the one that goes with the flying squirrel's [current] chosen touchpanel, eventually found it in a rockchip kernel source tarball somewhere.
so, I2C is on EOMA68: therefore capacitive touchpanels are automatically not a problem. just remember that the pull-down for I2C is *already* done on the CPU Card.
resistive panels: that's a different matter. they're analogue, so you'd need either a dedicated IC or to do it yourself with a voltage source (or two?) and any IC that has a couple of ADCs (or three?). to be honest, i'd recommend just using a dedicated IC. the one i used to be familiar with is a TI TSC230somethingsomething.... TSC2200. oh. arse. it's SPI.
hmmm, let's see... http://www.ti.com/lsds/ti/data-converters/touch-screen-controller-products.p... I2C tum te tum.... exclude automotive parts... lowest-priced item iiiis:
http://www.ti.com/product/tsc2014
ta-daaa :) ok, if you prefer a QFN package you'd have to use the tsc2004 which is $1.75 not $1.30 in 1k volumes.
that's with 5 mins of searching. if you spent a bit more time looking i'm sure there would be lower-cost options easily found.
is there a linux kernel driver for the TSC2014 and the TSC2004? answer: yes. http://www.ti.com/tool/tsc2004-linux-drv
so that's sorted.
l.