how does the nrf52832 decide to enter the swd mode?

[cgadgil]

hi

my question is really basic, but i am not able to find an answer anywhere else. I am trying to program the nordic using its SWDIO and SWCLK pins and am stuck as i get " emulator not found" error. I am wondering what the problem could be. How does the nrf52832 detect a swd programmer connected and decide to enter the debug mode as against running its existing code if any? 

is a reset or some specific signal on any other pin necessary?

I have used the nrf51822 before and i only connected SWDIO, SWCLK, VCC and GND and everything worked well. but with the nrf52832 i am having issues programming the IC.

thanks in advance for the answer

[RK]

what In Circuit Emulator or debugger are you using to try and program the chip? Segger? OpenOCD .. what? 

[cgadgil]

https://www.waveshare.com/wiki/ARM_Debugger

Although it does not mention the nordic microcontroller in the supported microcontroller list, since nordic is cortex M4 i believe it should still work?

[Håkon Alseth]

For the specific debugger that you're using, it seems that it has limited support according to this page: https://www.waveshare.com/arm-debugger.htm

It mentions that this only works with the nRF51822 board. I suspect that the manufacturer does not support other devices with this specific programmer, but I would recommend contacting them to double check.

Best regards,

Håkon

[cgadgil]

thanks!

yes it seems so.. i will check with the manufacturer. However i would still want to know the answer to my question "How does the nrf52832 detect a swd programmer connected and decide to enter the debug mode as against running its existing code if any? "

because i am not finding sufficient documentation on the reset process from hardware + firmware perspective at one place

[Håkon Alseth]

Hi,

 

The nRF51 has mux'ed the nRESET pin with the SWDIO pin, so the setup there is a bit different to other Cortex M-family devices. The nRF52832 has dedicated SWDIO/SWDCLK pins, thus it uses the standardized ARM DAP to enable the "debugger interface" (DIF). More info can be found in one of our white papers:

http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.whitepapers/dita/whitepapers/nwp_027/intro.html?cp=11_4

Cheers,

Håkon