nRF51 Dk damaged

[Bimal]

Hi,

I have my custom nRF51822 board, and i used to flash the firmware through nRF51 DK kit. As there are two ports through which we can load external boards i was using P20 connector as its mating connector is easy to get. Suddenly i found that while i was working with software part and custom board and nRF51822 where connected with P20 connector. It damaged my custom board SoC(nRF51822) and MCU of nRF51 DK board.

Can you please help me out for following quires/Observations:

• Now i am seeing that P20 SWDIO and SWDCLK are shorted with Ground of nRF51 DK.
• Also 3.3V(VDD) and GND are showing me shorted, so i guess MCU has damaged.
• It also shorted my custom board 3.3V and GND, show i replaced SOC(nRF51822) and now its working fine individually.
• Please tell me is there any protection required on SWD interface.
• Is there any specific reason for this damage.

Need your feedback, As this is stoping me from further process.

[Hung Bui]

@Bimal: It's pretty strange what you exerienced. What do you have on your external board ? Do you have any high voltage source on the external board that may shorted and burn the chips ?

Note that the SWD pins on the P20 or P19 is not connected the SWD pins on the nRF51 chip on the DK. So it's strange that replacing the nRF51 chip on the DK can fix the short between SWD pins on P20 to ground. I's suspecting the Atmel (Segger) chip on the DK is damaged.

Note that even there is VTG pin on the SWD port, you still need to provide the external board with it's power source. The VTG pin on the P20 port is only the input pin to detect the external board's power voltage.