Can't flash nrf51822 via SWD

[Kyrylo Mikos]

Hello. I'm newbie in nrf51 world so maybe my questions will be a bit stupid.

I bought few nrf51822 modules on Aliexpress. Photo: www.dropbox.com/.../77_1.jpg I bought STM32F103 for Black Magic Probe.

I flashed STM32F103 with this manual: medium.com/.../converting-an-stm32f103-board-to-a-black-magic-probe-c013cf2cc38c and it works.

After I wired nrf51822 to BMP (4 wires) but BMP can't see it: SW-DP scan failed!

I wired 3.3V to VCC (actually tried DCIN but without luck).

My question is: does this nrf51 board needs something to enter SWD mode? Maybe I forgot something?

[endnode]

No, nRF51 has SWD interface basically always available, there is no way how to kill it from SW. Chip can be read-back protected so some SWD instructions are unavailable but there is a way how to restore it (it will erase entire flash as side effect indeed). There are some procedures how to do this with SEGGER J-Link or even OpenOCD (you can search this Q&A forum) but the only official procedure how to do it are Nordic tools like nRFgo Studio or NRFJPROG and compatible JTAG/SWD HW probes (SEGGER J-Link).

[Kyrylo Mikos]

Thanks. It's weird but today I flashed board successfully with OpenOCD (Chinese ST-LINK v2). BMP still does not see the board. So will use OpecOCD in future.