Custom NRF51822 board issue while detecting

[sunny]

I have a Custom Board made by using nrf51822 soc but pc is unable to detect the board by using Jlink debugger. Stlink was able to detect only when frequency selected as 20khz and by using openocd, it is not able to detect at all. What could be the reason for stlink detecting only at 20khz or less? Any possible way to work it by using segger Jlink as min frequency in Jlink firmware is 100khz?

[Sigurd]

Hi,

This could be caused by long traces/cable length from the nRF51 to the debugger, or a bad connection. What voltage is supplied to the nRF51? Could you upload the schematic/layout? If you don’t want to share the schematic/layout here, you can summit a support ticket regarding this issue on MyPage.

[sunny]

Current I'm supplying 3.7 Volts to NRF board and it is connected to Jlink via Jumper Wires. Jumper can't be a problem or it can be? Sorry datasheet is not available for right now. The board was tested with JLink debugger with a speed of 20Khz. New Firmware of the board is not allowing to keep frequency below 100khz.

[Sigurd]

Have you remembered to connected VTref to detect the voltage on the nRF?

Also note that with 3.7V you are outside the recommended supply voltage for the chip (min 1.8V, max 3.6V). The chip can be powered up to 3.9V, but exposure to voltage between 3.6V and 3.9V may for prolonged periods of time may affect the reliability of the chip.

[sunny]

Voltage regulator IC is provided in the custom board and supplied VTref is showilg approx to 3.2V. I was able to work with STLink Debugger after putting board in reset mode. Now able to dump binaries using Keil and OpenOCD both with StLink Debugger