On Fri, Oct 16, 2015 at 4:41 PM, Peter Bouda peter@ubrew.it wrote:
keep the little piece of card, you need it! it has the pin-out assignments. so forget powering by the micro-usb, do this:
- flip the jumper from E5V to U5V
- cut off a random USB cable and strip down the black, red, white and
green
- solder 5V (Red) to pin 6 of CN7
- solder GND (black) to pin 8 of CN7
- solder USB+ (green) to pin 12 (PA12) of CN10
- solder USB- (white) to pin 14 (PA11) of CN10
then, plug it into a USB port of the development machine. then, use a screwdriver to short BOOT0 (pin 7 of CN7) to E5V (pin 6 of CN7), and at the same time press and then release the reset button (B2).
if you then do "lsusb" you should see a device come up "DFU mode" in the description. ta-daa, you can now upload a .bin file to it. you do that with any of the libopencm3-examples, you must do "make bin".
hm, that did not work, unfortunately, I cannot get into the DFU mode somehow. It will just start into the mode that is described in the Quick start section of the manual. I found some forum posts where people suggest to solder resistors to PA11 and PA12... but that should not alter the start mode, right?
that's for very older STM32F devices, where they did not have the resistors built-in. occasionally you might need 22R resistors to stop signals bouncing back-and-forth with incorrect impedance, but you shouldn't.
Any ideas what I could have done wrong?
it's not amazingly hard, this, there's not actually a lot to do, so the number of things wrong will be very small.
can you take a picture and make it available online, also compare against the photo here: http://rhombus-tech.net/community_ideas/laptop_15in/news/PCB2_prototype_prog...
btw if you haven't re-flashed the firmware at all, then by default it will come up with LD2 blinking happily. check first that that's what happens by returning the U5V jumper and plugging in a mini-usb cable.
btw you should *NOT* plug in a mini-usb cable at the same time as the USB cable across PA12 and PA11!
also make sure BOOT0 is shorted to E5V *before* pressing reset, then hold reset for at least 0.5 seconds, *then* release reset, then release BOOT0 screwdriver-short.
l.