2015-09-04 04:33 AM
2015-09-04 09:49 AM
2015-09-18 12:38 AM
Very bad designed pcb.
Difficult to see on the picture but it looks the traces are barely touching the pads of the stm. For example the xtal traces, but there are numerous of them. Buy for $4 an board on ebay to start with. http://www.ebay.com/itm/STM32F103C8T6-ARM-STM32-Minimum-System-Development-Board-Module-For-Arduino-DHUS-/321569700934?hash=item4adf0c3c462015-09-18 04:38 AM
Hi Edje
On real board everthing is ok and I checked them with a DMM in diode(Beep) mode.2015-09-18 05:59 AM
I like to build boards that are easy to debug, and work first time over. Putting a standard 20 or 10-pin ARM debug header makes that connectivity easier.
Check the supply pinsCheck the state of the NRST pinDouble check the SWD/JTAG connectivity, that you haven't mirrored or reversed what you think is pin 1, etc.Using the BOOT0 High, and USART1 PA9/PA10 trick you could confirm if it's just a debugger connectivity issue, or if the part is just not running.I think we've check the orientation, the supplies, especially the analogue ones, are the next. Check for opens/shorts. Check that the pin numbering is all correct in the design files, Make sure the netlist connects all the nets as you expect, and there aren't unconnected islands, and the schematic/net/pcb don't throw any design rule checks.2015-09-18 09:42 AM
Thanks Clive for reply
It's a puzzle to me what do you mean ''Check the state of the NRST pin''? because as you can see I have pulled it up with a 10KOhm then it's always is in High state. should I disconnect(cut out) the pull up resistor and check the state of the NRST? What information it will give me if NRST is High or Low?2015-09-18 03:50 PM
It's a bi-directional pin, the STM32 can clamp it low, this will occur if the POR circuit thinks the analogue supplies aren't above threshold, or the internal regulation isn't working.
The debugger should also be able to control it to get the part into a known condition.2015-09-19 05:40 AM
Thanks
I measured the NRST pin. it's 2.33 while the supply is 2.5. is it ok?2015-09-19 06:47 AM
Well that's a positive sign, so now you want to see if you can talk to the system loader.
2015-09-20 10:42 AM
It's a bit hard to do it because there is no pin header connected to PA9 and PA10.