Unable to flash due to high reset pin

RE: Unable to flash due to high reset pin

endnode — Thu, 23 Mar 2017 15:19:44 GMT

Good spot, you are right that nRESET is the same PIN as SWDIO on nRF51xxx. I guess it can really be HW problem or any of FWs (nRF5x or auxiliary SEGGER FW on DK board) causing PIN pulled HIGH. You could try to use another SEGGER (or similar JTAG/SWD) debugger/flasher, connect it to "Debug in" port of PCA10028 and try it that way (keep PCA10028 not powered from USB and supply 3V3 externally)...

RE: Unable to flash due to high reset pin

Bjarne Kvæstad — Thu, 23 Mar 2017 14:39:54 GMT

I've already tried to updgrade the J-Link FW, and there is still no difference. After studying the NFR51422-pinout, SWDIO and nRESET is the same pin, so if nRESET is pulled high it would not be possible to flash (or communicate) the MCU. I did measure 2.8V on this pin, I don't know where this voltage is coming from, maybe this is an hardware issue?

RE: Unable to flash due to high reset pin

endnode — Thu, 23 Mar 2017 14:09:16 GMT

Is RESET PIN state important if you simply use SWD commands and PINs? There should be the way how to use SEGGER tools directly in attempt to "recover" nRF5x chips (= remove read-back protection and erasing certain UICR registers which will cause erasing of whole chip), see this answer from RK.

RE: Unable to flash due to high reset pin

Vidar Berg — Thu, 23 Mar 2017 14:07:56 GMT

I've seen this isse before, but has always been able to recover by powercycling the kit. You could try to re-program the Jlink fw and see if that helps: put the kit in DFU mode and copy the following FW image to the BOOTLOADER drive.

RE: Unable to flash due to high reset pin

Bjarne Kvæstad — Thu, 23 Mar 2017 13:50:25 GMT

The debugger is set in bootloader mode if the reset button is held down during powerup, and is not the case here. I've now tried from an other computer with a simular setup, but with the same results, RESET-pin high...

RE: Unable to flash due to high reset pin

endnode — Thu, 23 Mar 2017 13:32:45 GMT

I've now noticed you have pushed IF BOOT/RESET button. Note that if you press it long time then you put auxiliary MCU (Atmel generic MCU with SEGGER J-Link OB FW or mBed FW) to bootloader mode. If so then it will stop working as SWD to target nRF5x chip on the board... if it is not the case then I would use different machine, there are several Q&As on this forum where users claim how something doesn't work for days and then it works instantly on different system...

RE: Unable to flash due to high reset pin

Bjarne Kvæstad — Thu, 23 Mar 2017 13:27:13 GMT

Both SEGGER J-link and NRFTOOLS applications was downloaded today, and should be the newest version. But it seems like Keil is using a old dll.

RE: Unable to flash due to high reset pin

endnode — Thu, 23 Mar 2017 13:10:37 GMT

Have you upgraded to latest SEGGER J-Link and NRFTOOLs/nRF Go Studio? It seems you are using old version (SEGGER J-Link V5.12f) but hard to tell from what you have here...