Unable to Connect j-link to nRF52832 on Production Board

[Nate Z]

I'm trying to debug firmware on our production device, but after programming the device a couple of times, I am unable to program.

Inside of Segger I see this log:

Connecting ‘J-Link’ using ‘USB’
Connecting to target using SWD
Loaded C:/Program Files/SEGGER/SEGGER Embedded Studio for ARM 5.10b/bin/JLink_x64.dll
Firmware Version: J-Link ARM V8 compiled Nov 28 2014 13:44:46
DLL Version: 6.88a
Hardware Version: V8.00
Target Voltage: 3.228
Device "NRF52832_XXAA" selected.
InitTarget() start
InitTarget() end
Found SW-DP with ID 0x2BA01477
Unknown DP version. Assuming DPv0
Scanning AP map to find all available APs
AP[0]: Stopped AP scan as end of AP map has been reached
Iterating through AP map to find AHB-AP to use
RESET (pin 15) high, but should be low. Please check target hardware.
InitTarget() start
InitTarget() end
Found SW-DP with ID 0x2BA01477
Unknown DP version. Assuming DPv0
Scanning AP map to find all available APs
AP[0]: Stopped AP scan as end of AP map has been reached
Iterating through AP map to find AHB-AP to use
Could not find core in Coresight setup
connect failed
Failed to connect to target.
No idcode detected.
Please check connection and Target Interface Type

j-flash shows this:

Connecting ...
 - Connecting via USB to probe/ programmer device 0
 - Probe/ Programmer firmware: J-Link ARM V8 compiled Nov 28 2014 13:44:46
 - Device "NRF52832_XXAA" selected.
 - Target interface speed: 4000 kHz (Fixed)
 - VTarget = 3.228V
 - InitTarget() start
 - InitTarget() end
 - Found SW-DP with ID 0x2BA01477
 - Failed to power up DAP
 - RESET (pin 15) high, but should be low. Please check target hardware.
 - InitTarget() start
 - InitTarget() end
 - Found SW-DP with ID 0x2BA01477
 - Failed to power up DAP
 - ERROR: Failed to connect.
Could not establish a connection to target.

Attempting to use nrfjprog --recover --log has this as output:

Console Output:
ERROR: JLinkARM DLL reported an error. Try again. If error condition
ERROR: persists, run the same command again with argument --log, contact Nordic
ERROR: Semiconductor and provide the generated log.log file to them.

Log:
[2021-Mar-02 12:42:43] [ info] --------------------------------------------------------------------------------
[2021-Mar-02 12:42:43] [ info] nrfjprog --recover --log 
[2021-Mar-02 12:42:43] [ info] nrfjprog version 10.12.1 
[2021-Mar-02 12:42:43] [ info] --------------------------------------------------------------------------------
[2021-Mar-02 12:42:43] [debug] [ nRF0x0] - open_dll
[2021-Mar-02 12:42:43] [ info] [ nRF0x0] - Load library at C:\Program Files (x86)\Nordic Semiconductor\nrf-command-line-tools\bin\JLINKARM_UNKNOWN_NRFJPROG.dll.
[2021-Mar-02 12:42:43] [ info] [ nRF0x0] - Library loaded, loading member functions.
[2021-Mar-02 12:42:43] [ info] [ nRF0x0] - Member functions succesfully loaded.
[2021-Mar-02 12:42:43] [ info] [Backend] - Logger callback at 0x182020 registered in Segger backend logger.
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] Logger callback at 0x182020 registered in JLink logger.
[2021-Mar-02 12:42:43] [debug] [nRFUnknown] - Just_open_dll_tagged_callback
[2021-Mar-02 12:42:43] [debug] [Backend] - open_dll
[2021-Mar-02 12:42:43] [ info] [Backend] - No J-Link DLL path was provided. Attempting to auto detect.
[2021-Mar-02 12:42:43] [ info] [Backend] - Load library at C:\Program Files (x86)\SEGGER\JLink\JLinkARM.dll.
[2021-Mar-02 12:42:43] [ info] [Backend] - Library loaded, loading member functions.
[2021-Mar-02 12:42:43] [ info] [Backend] - Member functions succesfully loaded.
[2021-Mar-02 12:42:43] [debug] [Backend] - dll_version
[2021-Mar-02 12:42:43] [ info] [Backend] - Segger dll version 6.88.a loaded.
[2021-Mar-02 12:42:43] [debug] [Backend] - set_core_data
[2021-Mar-02 12:42:43] [debug] [ nRF0x0] - enum_emu_snr
[2021-Mar-02 12:42:43] [debug] [nRFUnknown] - Just_enum_emu_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - enum_emu_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_enum_emu_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_get_num_emus
[2021-Mar-02 12:42:43] [debug] [ nRF0x0] - connect_to_emu_with_snr
[2021-Mar-02 12:42:43] [debug] [nRFUnknown] - Just_connect_to_emu_with_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - connect_to_emu_with_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - is_connected_to_emu
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_enum_emu_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_get_num_emus
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_connect_to_emu_with_snr
[2021-Mar-02 12:42:43] [debug] [Backend] - ---just_connect_to_emu_without_snr
[2021-Mar-02 12:42:43] [ info] [Backend] - Segger logging enabled.
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] Firmware: J-Link ARM V8 compiled Nov 28 2014 13:44:46
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] Hardware: V8.00
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] S/N: 4294967295
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] OEM: SEGGER
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] Feature(s): RDI,FlashDL,FlashBP,JFlash,GDB
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] TELNET listener socket opened on port 19021
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] WEBSRV Starting webserver
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] WEBSRV Webserver running on local port 19080
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 9.513ms returns "O.K."  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_GetHWStatus(...)  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.402ms returns 0  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("SetRestartOnClose = 0", ...).   
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.009ms returns 0x01  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("DisableFlashDL", ...).   
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.006ms returns 0x00  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...).   
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.005ms returns 0x00  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetHookUnsecureDialog  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetHookUnsecureDialog(...)
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.023ms returns 0  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_TIF_Select(JLINKARM_TIF_SWD)  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 1.250ms returns 0x00  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetSpeed(2000)  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.230ms  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_GetSN()  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] - 0.010ms returns -1  
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-Mar-02 12:42:43] [ info] [Backend] - JLinkARM.dll reported "-1", an unknown error.
[2021-Mar-02 12:42:43] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_Close()  
[2021-Mar-02 12:42:43] [debug] [ nRF0x0] - close_dll
[2021-Mar-02 12:42:43] [debug] [nRFUnknown] - Just_close_dll
[2021-Mar-02 12:42:43] [debug] [Backend] - close
[2021-Mar-02 12:42:43] [debug] [Backend] - disconnect_from_emu
[2021-Mar-02 12:42:43] [debug] [Backend] - is_connected_to_emu
[2021-Mar-02 12:42:43] [debug] [Backend] - Segger Backend closed.

A couple of items of note:

1. I have several j-flash devices and even the nRF-52 DK, the same results (less log output on the nRF52-DK)
2. I have tried rebooting and on multiple computers
3. I have tried this on several production devices. They let me write to them sometimes
4. I have found and terminated an errant j-flash process in the past which let me write to the device
5. When writing the firmware to the nRF-52 DK or the Fanstel EV-BM832 board, I do not have any trouble
6. The production device is using the internal oscillator settings rather than a crystal. These settings are:
   

       nrf_clock_lf_cfg_t const clock_lf_cfg =
       {
           .source       = 0,
           .rc_ctiv      = 16,
           .rc_temp_ctiv = 2,
           .accuracy     = 7
       };

I am a little worried that the header got a little fancy with the "ESD" protection. 

Any ideas or help would be appreciated!

[Jørgen Holmefjord]

Hi,

It is possible that the firmware you have flashed enables pin reset, while the board leaves the reset pin floating. In that case, you can try to pull the reset pin directly to VDD and then do a "nrfjprog --recover".

Best regards,
Jørgen

[Nate Z]

I wish I could give more detail of an exact cause, but I looked at every schematic I've seen for any projects we've ever used for this chip, and it's never had such fancy ESD protection so I decided to de-populate that circuitry. It worked like a charm! My guess based on the logs is that the Zener diode on the RESET line didn't allow the programmer to pull it up high enough most of the time.