STM32h745iik6 doesn't execute code on power up, execution starts after i press reset manually

dplogiic · ‎2024-06-19

Hello everyone,

I'm experiencing an issue with my STM32 microcontroller (STM32h745iik6 own board) where it doesn't execute the code upon power up. However, when I press the reset button, the code executes as expected. I'm looking for some guidance to resolve this problem.

bellow i attach some schematic. please suggest how can i solve this challenges.

Peter BENSCH · ‎2024-06-19

Please place a capacitor of approx. 100nF between NRST and GND.

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

SofLit · ‎2024-06-19

You need to check VCAP capacitors. Did you mount them? how much?

You need also to provide the complete schematics (mostly the MCU part) to help you efficiently.

Also need to place a capacitor on NRST/GND as stated by my colleague @Peter BENSCH

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

dplogiic · ‎2024-06-20

hello @Peter BENSCH @SofLit ,

I trying to 1) place 100nF/25v cap near nsrt

2) i try to disconnect all and only place 100nF cap with GND like below

but even not work.

3) if i disconnect reset ckt so nsrt pin present 3.263v.. and just i touch any cable to nsrt then controller reset and code execute well.. ......

So actually what is issue.. any pull up/ pull dawn needed to add externally.

4) on Boot0 pin connection like below

add 1uf/25v cap to Boot0 with 3.3v and 10k gnd

my board upload program by external stlinkv3 programmer... if i remove 1uF cap of boot0 then error while upload code... but if i connect like above then program upload successfully... and debug also.. but i remove stlink then code not execute until i press nsrt every power up.

Peter BENSCH · ‎2024-06-20

It is definitely wrong to place a capacitor from BOOT0 to VDD. Similarly, no pull-up is necessary at NRST, even if it is incorrectly shown in some colourful "Pills".

@SofLit has pointed out that the corresponding capacitors must also be connected to the VCAP pins. For your STM32H745IIK6 in the UFBGA176+25, these are A4, A14 and R13. Have you done this?

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

dplogiic · ‎2024-06-20

Vcap A4, A14, R13 connected with 2*2.2uF/50v---> GND

Peter BENSCH · ‎2024-06-20

With the current information, this is difficult to assess. It could be a layout problem, one with the solder joints of your UFBGA, and so on.

If you touch the open NRST pin with your finger, you only inject noise, which trigger the same thing as a short low pulse.

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

SofLit · ‎2024-06-20

As I already suggested, you need to share your schematics. We don't have the full picture here so we cannot help you efficiently. Also share your ioc file to check the init.

You can also refer to the AN4938 "Getting started with STM32H74xI/G and STM32H75xI/G
MCU hardware development" and also to our reference design stm32h745i-disco schematics.

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.