[Arm-netbook] IC for analog and digital buttons (EOMA-68)
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Thu Aug 7 15:11:10 BST 2014
On Thu, Aug 7, 2014 at 3:00 PM, krasi gichev <krasimirr at gmail.com> wrote:
> Firmware update of newer STM32s could be done over USB too - you don't need
> separate UART for this. Just wire BOOT pin (pins) to GPIO(s) from EOMA to
> allow entering firmware update mode (DFU over USB).
> 64pin seems an overkill
... until you realise that there are around 32 GPIOs needed and
around 10 ADCs, then you have I2C, SPI, UART and others, it ends up at
quite a lot of pins.
>- there a lot of other package options, e.g. 48pin
> QFN, not to mention the BGA variants. Also, F103 is quite old one, probably
> the price might be good, but I would recommend some of newer ones (Cortex-M0
> even) - look at F0, F2, F3 series. A good option could be this: STM32F071CB,
> the price goes below $2.50 for 100pcs, and it seems to have all you need -
oo. it doesn't have USB, but it does have SPI, so apart from being a
slight pain (having to write a custom linux kernel driver) it would be
> SiLabs "Precision 32" are also nice ones - very well balanced peripherals
> and packages (e.g. QFN40, SiM3U154), built in regulator from 5V (if needed).
> But the price is higher.
> 2014-08-07 12:07 GMT+03:00 Miguel Garcia <gacuest at gmail.com>:
>> 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.
>> 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? Or do we have to add the STM32F
>> and the digital GPIO IC?
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