nrf52832 can work but can't download the program

[tianqige]

I use the nrf52832. In the beginning,I can download the code and it works well. And suddenly,Keil told me "No Cortex-M SW Device Found",when I change a new chip it can work. But there 4 chips have been destroyed. I want to konw the reason.

[FormerMember]

The message "No Coretex-M SW Device Found" will typically appear if the chip is not powered. When this message appear, could you check that the chip is powered?

Does it happen that the power supply exceed the maximum allowed voltage?

Are there any likely potential things that could cause short circuit of the chip?

Do you have followed the reference layout/schematic?

[FormerMember]

When you are not able to program the chip, are you able to measure that it is powered? Measure that the voltage is correct?

What happens if you use nrfjprog from the command line and try to recover the chip? nrfjprog --recover -f nrf52?