2015-11-17 05:59 AM
Hello, this is my first post.
It is the first time I use an STM32 Device, I am familiar with 32Bit processors of TI so far.I did a new PCB connected with the ST-Link programmer of a Nucleo board. But I can not connect to my board. I am using the STM32 St-Link Utility.My configuration:TQFP64Pin 19,32,48,64,13,1 on 3V3Pin 31, 47, 18, 63, 12 on GNDPin 30 on 4.7uF to GND (VCAP)25 MHz crystal on Pin 5 & 6Pin 60 (Boot0) connected to 10k to GNDPin 46 to ST-Programmer SWDPin 49 to ST-Programmer CLK Pin 7 to ST-Programmer NRSTThe programmer also has GND of the board.All other Pins are left floating.Power consumption 0.3 mA! The CPU seems not to run.Pin 1 is at the lower left if the text on the chip is readable.The voltage on the VCap_0 is 0V.It is a bit confusing, I just have seen that the VCAP_1 (Pin 30) capacitor is not populated and has been shorted to ground on the Nucleo board.Could anyone give me an advice how to handle this situation?Thanks in advanceChris2015-11-17 07:07 AM
you'll get more chance to swd into the MCU while BOOT0 is tied to VCC (as per 2606). If your MCU has BOOT1, tie it to the ground.
BTW it is also likely your custom HW being screwed with solder bridges, mirrored footprint or any other kind of misfab.2015-11-18 04:36 AM
2015-11-18 05:33 AM
Chris,
VCAP1 must be connected to the ground through a low-esr (<1ohm) ceramic capacitance (4.7µF). Resulting voltage sb. around 1.2V Everything else looks good to me (i am not an HW guy). I guess that the MCU will draw somewhere between 1 and 10mA.2015-11-18 05:53 AM
Well it does seem to be indicative of power not reaching the part. I'd probably look very carefully at VDDA.
Measure the voltage on NRST.Do you have a schematic or gerber for this board? Have you checked the netlist, especially the power connectivity, and have you checked continuity on an unpopulated, or partially populated board.I would go with the DM suggestions related to VCAP1, but as indicated you should see 1.25V or so there. That you do not suggests the regulator is not on. Most often seen where the orientation is wrong, but you indicate you've looked at that.2015-11-18 07:07 AM
Juhhu :) You are great!
It is working now, as mentioned the VDDA was not populated yet and open.Next time I will measure everything twice.Thanks again for helping me!Cheers,Chris2015-11-18 07:38 AM
Hum ... shall we understand that pin 13 was not really connected to 3.3V ?
2015-11-18 08:29 AM
Hum ... shall we understand that pin 13 was not really connected to 3.3V ?
That would seem to be the inference. When reality defies the stated facts, I tend to question the facts, not the reality.2015-11-18 10:34 PM
Yes.
For the VDDA I used a LC Filter. This filter I have not populated then thats because the it was floating.I have no idear what I have been measured there :)Cheers and a good rest of the week,Chris