STM32F030K6 start only with reset tie to VCC

[piotr239955_st]

Posted on May 03, 2017 at 19:18

I have device with STM32f030K6T6. Since one moment, I am not able to start this uP without shorcircuiting nReset signal to VCC. Originally I had RC circuit on this line. When this problem had occured I modified it removing resistor (leaving capacitor connected between nReset and GND). Still doesn't work. Currently I'm running very simple program with for(;;) loop.

Main question is: what kind of setting may cause that? At some point I was using settings in ST-Link with 'Program under reset', but now I change that to 'normal & autodetect' but behavior is still the same.

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[Tesla DeLorean]

Posted on May 03, 2017 at 19:23

I would guess you don't have VDDA wired up properly to a supply.

Short circuiting the pin suggests come chronic design failure on your end.

[piotr239955_st]

Posted on May 03, 2017 at 19:29

VDDA is connectected directly to VCC and 100nF capacitor is placed as close as possible.

[Tesla DeLorean]

Posted on May 03, 2017 at 19:38

If the supply is below threshold on VDDA the device will have NRST clamped internally.

If NRST with a pull-up is LOW, something in the circuit is driving it there or clamping. The STM32 won't naturally do that. You need to look critically at the circuits on the board, review the netlist carefully. Measure the voltage on VDDA.

Double check pin list against datasheet, and that part is correctly orientated.