[Arm-netbook] Block Diagram EOMA-68 Handheld Games Console

Luke Kenneth Casson Leighton lkcl at lkcl.net
Sat Sep 6 17:39:22 BST 2014

On Sat, Sep 6, 2014 at 10:37 AM, Miguel Garcia <gacuest at gmail.com> wrote:
> 2014-09-05 13:48 GMT+02:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:
>> there are two EINT lines on EOMA68.  i suggest that one of them be
>> connected to the AXP209, and the other to the STM32F072, although
>> because there are only 2 this leaves some slight issue with the
>> touchpanel to resolve (in linux kernel source, which will need
>> modification).
>> the problem is this: things like the touchpanel it is fairly essential
>> (because you want to wake up the entire device based on an EINT) to
>> have external interrupt.
>> one alternative to modifying the linux kernel source is to have a NAND
>> (NOR?) IC multiplexing multiple IRQ lines from various peripheral ICs
>> onto the one EINT line.
>> another alternative is to wire the AXP209 to the STM32F (on one of its
>> GPIOs, then put that into EINT mode), then have the STM32F software
>> generate a simple GPIO pull-up out to one of the EOMA68 EINTs.
>> so instead of doing the multiplexing using a NAND (NOR) gate IC, you
>> do it in software (firmware) instead.
>> then you can do whatever you want, without modifying any linux kernel source.
> Thanks.
> And, what is your recommendation?

 i'd suggest multiplexing them all via the STM32F07xx onto one pin.
this will mean that all drivers which use that pin will all receive
interrupts whenever any of the other devices generate one but that is
much more preferable to polling

>> * Headphone detect
> What is the INT/IRQ pin here?

 i don't understand the question.  the headphone detect pin is the INT/IRQ pin.


> Thanks.
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