AnsweredAssumed Answered

STM32F107RC - Very low external resistor on NRST pin

Question asked by lisowski.mariusz on Jun 3, 2011
Latest reply on Sep 29, 2012 by mcconaghy.peter
Hi,
I want to build circuit with STM32F107RC. I projected PCB and chcek all wires with any avaluation kit board. When I turn power on all circuit take about 9 mA. I chcecked all power supply pins aroud microcontroller and I egazmined all voltages.
All voltages was 3,331V. I egzamined BOOT0 and BOOT1 switches. All is OK. BOOT0 is logical 1, BOOT1 is logical 0. On NRST pin I have 0,441V with pull-up resistor 10k. When I exchange on NRST pin resistor to 100 ohm on pin I have 3,110V and microcontroller runs. General current is about 50mA and all look very good.
In this case I can use JTAG for upload firmware and I can use RS-232 for upload firmware.

Why my STM32F107RC requires more low resistance on pull-up NRST pin ? I have 2 this components and all 2 components work similary. Would you like tell me what I do bad ? I read more materials in net, but anybody don't written about this problem in the past.

Best regards,
Mario

Outcomes