Stm32f042f6 tssop package , when i am powering ,microcontroller is not starting ,even if i use hard reset . its only starting when i connect ST link( SW Debug)

[SKira.1]

YStm32f042f6 tssop package , when i am powering, microcontroller is not starting ,even if i use hard reset . its only starting when i connect ST link( SW Debug)  mode.I am using external clock 8 mhz.

I have attached Circuit diagram !! i tried with couple of MC but still same problem..

[KnarfB · Accepted solution]

PB8 is also the BOOT0 pin. You either want to add a pull-down here to ensure flash boot mode or override that feature by programming the USER option bytes in flash.

[SKira.1]

Thank you !! Now its working!!​