On Thu, Aug 7, 2014 at 10:07 AM, Miguel Garcia gacuest@gmail.com wrote:
2014-08-07 10:13 GMT+02:00 Luke Kenneth Casson Leighton lkcl@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@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
yes.
and the digital GPIO IC?
no.
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.
l.