internal command error in keil and can not connect target in stm32 utility

[SEMad]

Hi.

i was working on a custom f407ZEx board along with ssd1963 but after some repeatitive plug-on and plug-off the stlink (v2) and ssd1963 died. i changed both of them but after that the mcu can't be reprogrammed. in keil "internal command error" and in stm32 st-link utility "can not connect target".

 i tried changing framework and rest mode but no use!

can anyone help me?

thanks.

[Tesla DeLorean]

The external ST-LINK/V2 needs pin 1 or 2 provided with Target VCC

If the STM32 is non-functional and non-communicative, then you'll get these kind of failures.

Check the NRST level.

Check the voltages/capacitors on the VCAP pins.

See if you can connect with BOOT0 pulled High.

Check signs of life via the System Loader and USART1 or USART3, see App Note AN2606