[Arm-netbook] IC for analog and digital buttons (EOMA-68)
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Wed Aug 6 13:18:26 BST 2014
On Wed, Aug 6, 2014 at 1:19 PM, Miguel Garcia <gacuest at gmail.com> wrote:
> A basic sketch of the block diagram:
so, things that are missing from the diagram:
* digital GPIO IC connects its IRQ-OUT to EINT0-IN on EOMA68
* one GPIO IC IN pin is needed for MicroSD "detect"
* EOMA68 PWM out goes to LCD PWM
* 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 you probably want at least 2 16-pin Digital GPIO ICs because that's
quite a lot of GPIO. you have two EINTs so you can at least chain all
the EINT IRQs together.
if you start using USB (with an STM32F) then you will need 2 USB hubs
(or drop the USB Flash Drive idea)
if you use UART (with an STM32F) i would be concerned about the speed
/ latency of the control protocol communicating data.
honestly i think you are better off with discrete GPIO and ADC ICs
(SPI for preference, I2C otherwise).
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