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

[krasi gichev]

Yep, 071 is good if host connection is either I2C or SPI. There are 2 I2C
controllers so it can run as gateway.
But for USB there is STM32F072CBT6 - at Digikey it is priced at 2.37USD for
1000pcs -
http://www.digikey.com/product-detail/en/STM32F072CBT6/497-14645-ND/4815292.
This one is in 48 pin. If more pins are needed, just switch
to: STM32F072RBT6 -
http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823/PF259605





2014-08-07 17:11 GMT+03:00 Luke Kenneth Casson Leighton <lkcl at lkcl.net>:

> 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
> -
> > http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN7/PF259662
>
>  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
> okay.
>
>
> > 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?
> >>
> >> Thanks.
> >>
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