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

Luke Kenneth Casson Leighton lkcl at lkcl.net
Thu Aug 7 10:14:44 BST 2014

On Thu, Aug 7, 2014 at 10:07 AM, Miguel Garcia <gacuest at gmail.com> wrote:
> 2014-08-07 10:13 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
>>  blegh - and you need 2 of them _and_ 2 analog ICs as well. that's
>> starting to make the STM32F103 (64-pin variant) look attractive.  and
>> i know you can get that at around the $2.50 mark in 10k volumes.
>>  *sigh* ok do you really need that USB Flash thing?  because of a) the
>> cost (at least $4.50) b) the number of ICs (4) it's starting to tip in
>> favour of the STM32F again, i get the feeling you'd be better off
>> wiring up the STM32F as a USB 1.1 device.  you'll also need to wire up
>> the UART to the EOMA68 interface and a couple of other pins to put it
>> into "firmware upload" mode, but that's ok.
>>  the advantage there is that i have some GPL'd KiCAD designs with
>> STM32F already in them (or have found some out there when i last
>> checked).
> Yes, the USB flash drive can be removed.
> I think Daniel also prefers a microcontroller.

 i'll check and see what i have on the KiCAD front, tonight.

> 2014-08-06 14:18 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
>>  * one GPIO IC IN pin is needed for MicroSD "detect"
>>  * digital GPIO IC OUT pin needed for power-up of LCD
>>  * accelerometer IRQ goes to digital GPIO IC IN
>>  * digital GPIO IC IN pin connects to IRQ-OUT of AXP209
>>  * digital GPIO IC IN pin connects to Headphone-detect (in case you
>> want to alter volume on headphone-out)
> So, do we connect all this to STM32F?

 yes.  and the analog ADC stuff as well.  an STM32F can cope
admirably.  i have some test code kicking about so can help out there.

> Or do we have to add the STM32F


> and the digital GPIO IC?


 the nice thing about using the USB interface is that a it's pretty
quick (ok 11mbits/sec) but also IRQs etc. are all handled over USB.

 the down-side is you'll need to write both the firmware on the STM32F
as well as a matching library, but hey that should be fine: i'd
suggest doing something like a USB-HID device and a USB-Mouse device,
there is plenty of example code for both.  anything else you can do as
say a USB-ACM (modem) to read unusual stuff.


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