2011-06-03 02:59 PM
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, Mario2011-06-03 04:30 PM
You don't have the part wired properly, either you have something external on NRST, or the voltages on VDD,VDDA are wrong and the power supply supervisor is trying to hold the device in reset.
50 mA seems kind of high. You don't provide a schematic so we're left to guess.2011-06-04 12:55 AM
Hi,
I attached schematic also in PDF format. It is very, very simple solution because I will use thismicrocontroller for FFT transformation for measurement. In this aplication I had low dinisity microcontrollerSTM32F101 in the past andall was right. Regards, Mario ________________ Attachments : VMF-4_sch1.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0rM&d=%2Fa%2F0X0000000beb%2FotxO4Nm9CKZwpfauk.bwW.FFJ3NL9oahucErX5sDlZ0&asPdf=false2011-06-04 04:43 AM
I'd check the part placed for C20.
2011-06-04 02:12 PM
2012-09-29 05:33 AM
I had a similar problem with nRST being low. Clive1's suggestion to check Vdda was spot on - my filter resistor was too big and this was only 1.8V. Once I dropped the resistor so the voltage was higher the problem went away.
Thanks Clive1!