STM32F407 Boot Loader

[saiteja]

 I can't get into boot loader mode (from what i can tell). The PC won't detect the USB port etc.

What I've tried:

• I tried dumping the code to STM32F407 MCU through RS232(Flash loader), com port is detecting after that when we enter next it is showing No response from the target, Boot load can't be started
• I tried connecting with Ulink2 debugger and in Keil software controller is detecting then i rebuild the code but it is not uploaded in to the controller
• Checked the power and ground pins (all good)
• Checked the power quality. Its super stable and there are no spikes anywhere. (Goes through a 3.3v regulator)
• BOOT1 is hooked up to GND, BOOT0 is on a push button with a 10k pulldown (goes high when pressed)

Same Circuit and same design 10PCB's are there in that 3 are having this issue. How to solve this Problem?

Thanks in Advance

[saiteja]

Is there anyone who know the solution?

[Tesla DeLorean]

A solution would depend on what's going on with the board and chip.

I'd probably check how the reset is occurring, and try to debug what code is actually running​, and upload my own.

USB would be dependent on HSE starting properly.​

[saiteja]

Hi.... If only with USB it is not working means we can consider a code problem but here some PCB's are taking but only one or two giving the issue. Those boards even i tried to dump code through ulink2 debugger but still it is not taking but controller is detecting in Keil 5 software.