My nrf52840 can't boot up after power on,unless it was connected to JLINKRTTVIEW

[melancholyl]

It's strange,

My nrf52840 can't boot up after power on,unless it was connected to JLINKRTTVIEW,

If I disconnected the JLINKRTTVIEW, the device will stop running,
Connect again and it will start running again.

00> [01:58:53.135,620] <err> sx12xx_common:  TX DONE!
00> [01:58:53.935,699] <inf> lora_send: Data sent!
00> [01:58:54.142,517] <err> sx12xx_common:  TX DONE!

(Connection lost)  //disconnect and connect to JLINKRTTVIEW and device reboot agagin
00> *** Booting Zephyr OS build v2.3.0-rc1-ncs1-1446-g26216d1f7e09  ***
00>  
00> [00:00:00.039,184] <inf> lora_send: BIND PA
00> [00:00:00.039,215] <inf> lora_send: BIND PA SUCCESS!

[Vidar Berg]

Hello,

It shouldn't be necessary, but please try to disable logging over RTT and see if it still will not boot. You may also try to run "nrfjprog --readregs" to read out the Program counter (PC) register and see where the program gets stuck.

[melancholyl]

Hi,

If I disable logging over RTT,SOC will not run even I connected it to RTT Viewer

nrfjprog --readregs:

R0:   0x00000000
R1:   0x00000001
R2:   0x00001FBC
R3:   0x00000000
R4:   0x000063D1
R5:   0x20000D64
R6:   0x00000000
R7:   0x00000000
R8:   0x00000000
R9:   0x00000000
R10:  0x00000000
R11:  0x00000000
R12:  0xEE532F48
SP:   0x20001B28
LR:   0x00006F3D
PC:   0x00004296
xPSR: 0x61000000
MSP:  0x20002338
PSP:  0x20001B28

[Vidar Berg]

Thanks. The readout shows that the code is not stuck inside any interrupt context at least. Are you able look up the PC address (0x4296) to see where in the program it's stuck? Also, did you check if it gets stuck on the same address with RTT enabled?

[melancholyl]

Hi,I don't know how to check this address,

BTW,the same program runs normally on nrf52840dk (on-board JLINK), and now the issue is with our mass-produced SOC

[melancholyl]

Hi,I found similar issue :nrf51-wont-run-without-debugger

this may also be related to the state of SWDIO