J-link EDU mini can't connect to nRF52840

[Kageni]

Hi a bit a noobie here, but I can't connect to my nRF52840 on my custom board that I made. I have tried both an ST-link V2 with openocd, flashing it into a black magic probe, and everything else I could think of. When that didn't work, I figured it would be easier wwith a J link, so I picked up a j-link edu mini from ada fruit and have been trying that. I have tried nrfjprog, J-link commander, and arduino and they all have not been able to connect to the target. I make a connection to the J link, it is only connecting to the target that fails. I tried to produce a log with nrfjprog --recover --log, but it either isn't producing a log file or I can't find it. I am using this nRF52840 module https://freqchina.en.alibaba.com/product/62501832603-810441729/bluetooth_5_0_module_mesh_module_zigbee_ANT_nRF52840_module_PTR9818.html. I have Swclk, swdio, vdd, and ground coming off the module into a 4 pin SWD connector, and connected those to my J-link via SWD.

[Kageni]

Jared said:

Hi,

I don't have any experience with this module, nor can I prove that it's actually a real one. We have seen that people have bought non-legit from sites such as Alibaba and Ebay and then have connection issues.

Nevertheless,

Assuming that it's actually a real nRF inside:

For SWD to work you need to route out the:

• VCC
• SWDIO
• SWDCLK
• RESET(optional)

You also need to make sure that the nRF is supplied when you try to debug. It seems that you are supplying the nRF 3V3 via the debug interface, but I can't see where the supply is connected to the debugger?

regards

Jared 

Hi I have the 3V3, SWDIO, SWCLK, and ground coming off the board with a 4 pin header. I connected 3V3 -> Vref, SWDIO -> SWIO, SWCLK ->CLK, and GND -> GNDP

[Jared]

Kageni said:

Hi I have the 3V3, SWDIO, SWCLK, and ground coming off the board with a 4 pin header. I connected 3V3 -> Vref, SWDIO -> SWIO, SWCLK ->CLK, and GND -> GNDP

 Ok perfect, in addition to this you need to make sure the board is supplied externally while trying to connect to it. 

[Kageni]

Board is connected to USB and showing 3.3V volts at 3V3. I tried to run nrfjprog and this is the log.

[2021-May-27 04:22:46] [ info] --------------------------------------------------------------------------------
[2021-May-27 04:22:46] [ info] C:\Program Files (x86)\Nordic Semiconductor\nrf-command-line-tools\bin\nrfjprog.exe --recover --log
[2021-May-27 04:22:46] [ info] nrfjprog version 10.12.1
[2021-May-27 04:22:46] [ info] --------------------------------------------------------------------------------
[2021-May-27 04:22:46] [debug] [ nRF0x0] - open_dll
[2021-May-27 04:22:46] [ info] [ nRF0x0] - Load library at C:\Program Files (x86)\Nordic Semiconductor\nrf-command-line-tools\bin\JLINKARM_UNKNOWN_NRFJPROG.dll.
[2021-May-27 04:22:46] [ info] [ nRF0x0] - Library loaded, loading member functions.
[2021-May-27 04:22:46] [ info] [ nRF0x0] - Member functions succesfully loaded.
[2021-May-27 04:22:46] [ info] [Backend] - Logger callback at 0xab2020 registered in Segger backend logger.
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Logger callback at 0xab2020 registered in JLink logger.
[2021-May-27 04:22:46] [debug] [nRFUnknown] - Just_open_dll_tagged_callback
[2021-May-27 04:22:46] [debug] [Backend] - open_dll
[2021-May-27 04:22:46] [ info] [Backend] - No J-Link DLL path was provided. Attempting to auto detect.
[2021-May-27 04:22:46] [ info] [Backend] - Load library at C:\Program Files (x86)\SEGGER\JLink\JLinkARM.dll.
[2021-May-27 04:22:46] [ info] [Backend] - Library loaded, loading member functions.
[2021-May-27 04:22:46] [ info] [Backend] - Member functions succesfully loaded.
[2021-May-27 04:22:46] [debug] [Backend] - dll_version
[2021-May-27 04:22:46] [ info] [Backend] - Segger dll version 7.20.  loaded.
[2021-May-27 04:22:46] [debug] [Backend] - set_core_data
[2021-May-27 04:22:46] [debug] [ nRF0x0] - enum_emu_snr
[2021-May-27 04:22:46] [debug] [nRFUnknown] - Just_enum_emu_snr
[2021-May-27 04:22:46] [debug] [Backend] - enum_emu_snr
[2021-May-27 04:22:46] [debug] [Backend] - ---just_enum_emu_snr
[2021-May-27 04:22:46] [debug] [Backend] - ---just_get_num_emus
[2021-May-27 04:22:46] [debug] [ nRF0x0] - connect_to_emu_with_snr
[2021-May-27 04:22:46] [debug] [nRFUnknown] - Just_connect_to_emu_with_snr
[2021-May-27 04:22:46] [debug] [Backend] - connect_to_emu_with_snr
[2021-May-27 04:22:46] [debug] [Backend] - is_connected_to_emu
[2021-May-27 04:22:46] [debug] [Backend] - ---just_enum_emu_snr
[2021-May-27 04:22:46] [debug] [Backend] - ---just_get_num_emus
[2021-May-27 04:22:46] [debug] [Backend] - ---just_connect_to_emu_with_snr
[2021-May-27 04:22:46] [debug] [Backend] - ---just_connect_to_emu_without_snr
[2021-May-27 04:22:46] [ info] [Backend] - Segger logging enabled.
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Firmware: J-Link EDU Mini V1 compiled Feb 18 2021 11:25:23
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Firmware: J-Link EDU Mini V1 compiled Feb 18 2021 11:25:23
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Decompressing FW timestamp took 115 us
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Hardware: V1.00
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] S/N: 801032241
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] OEM: SEGGER
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Feature(s): FlashBP, GDB
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Looking for J-Link GUI Server exe at: C:\Program Files (x86)\SEGGER\JLink\JLinkGUIServer.exe
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] Forking J-Link GUI Server: C:\Program Files (x86)\SEGGER\JLink\JLinkGUIServer.exe
[2021-May-27 04:22:46] [ info] [  JLink] - [Info    ] [JLink     ] J-Link GUI Server info: "J-Link GUI server V7.20 "
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] TELNET listener socket opened on port 19021
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] WEBSRV Starting webserver
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] WEBSRV Webserver running on local port 19080
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 3119.851ms returns "O.K."  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_GetHWStatus(...)  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.353ms returns 0  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("SetRestartOnClose = 0", ...).   
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.291ms returns 0x01  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("DisableFlashDL", ...).   
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.010ms returns 0x00  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...).   
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.244ms returns 0x00  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetHookUnsecureDialog  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetHookUnsecureDialog(...)
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.187ms returns 0  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_TIF_Select(JLINKARM_TIF_SWD)  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.692ms returns 0x00  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_SetSpeed(2000)  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.302ms  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_GetSN()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.012ms returns 801032241  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [debug] [Backend] - ---just_load_core_data
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("CORESIGHT_SetIndexAHBAPToUse = 0", ...).   
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.003ms returns 0x00  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_ExecCommand("device = Cortex-M4", ...).   
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] XML file found at: C:\Program Files (x86)\SEGGER\JLink\JLinkDevices.xml
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] C:\Program Files (x86)\SEGGER\JLink\JLinkDevices.xml evaluated successfully.
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] Device "CORTEX-M4" selected.
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] Device "CORTEX-M4" selected.
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 63.229ms returns 0x00  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [debug] [ nRF0x0] - read_connected_emu_snr
[2021-May-27 04:22:49] [debug] [nRFUnknown] - Just_read_connected_emu_snr
[2021-May-27 04:22:49] [debug] [Backend] - read_connected_emu_snr
[2021-May-27 04:22:49] [debug] [Backend] - is_connected_to_emu
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_IsOpen()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.074ms returns 0x01  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [debug] [ nRF0x0] - read_device_family
[2021-May-27 04:22:49] [debug] [nRFUnknown] - Just_read_device_family
[2021-May-27 04:22:49] [debug] [Backend] - is_connected_to_emu
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_IsOpen()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] - 0.012ms returns 0x01  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_Lock()  
[2021-May-27 04:22:49] [debug] [Backend] - read_debug_port_idr
[2021-May-27 04:22:49] [debug] [Backend] - read_debug_port_register
[2021-May-27 04:22:49] [debug] [Backend] - ---just_read_debug_port_register
[2021-May-27 04:22:49] [debug] [Backend] - coresight_configure
[2021-May-27 04:22:49] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_CORESIGHT_Configure()  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 100.089ms returns 0  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [debug] [Backend] - ---just_select_debug_port_register
[2021-May-27 04:22:50] [debug] [Backend] - Select AP 255, DP Bank 0, AP Bank 255
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000)  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.514ms returns -1  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [ info] [Backend] - JLinkARM.dll reported "-1", an unknown error.
[2021-May-27 04:22:50] [debug] [Backend] - ---just_abort_debug_action
[2021-May-27 04:22:50] [ info] [Backend] - Attempting to clear any configuration errors in debug port before closing connection.
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x00, 0x0000001F)  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.492ms returns -1  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [ info] [Backend] - JLinkARM.dll reported "-1", an unknown error.
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.039ms  
[2021-May-27 04:22:50] [debug] [ nRF0x0] - close_dll
[2021-May-27 04:22:50] [debug] [nRFUnknown] - Just_close_dll
[2021-May-27 04:22:50] [debug] [Backend] - close
[2021-May-27 04:22:50] [debug] [Backend] - disconnect_from_emu
[2021-May-27 04:22:50] [debug] [Backend] - is_connected_to_emu
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_IsOpen()  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.014ms returns 0x01  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [debug] [Backend] - ---just_disconnect_from_emu
[2021-May-27 04:22:50] [debug] [Backend] - is_connected_to_device
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_IsConnected()  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.013ms returns FALSE  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [debug] [Backend] - ---just_is_debug_region_powered
[2021-May-27 04:22:50] [debug] [Backend] - ---just_read_debug_port_register
[2021-May-27 04:22:50] [debug] [Backend] - is_connected_to_emu
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_IsOpen()  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.012ms returns 0x01  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_Lock()  
[2021-May-27 04:22:50] [debug] [Backend] - ---just_select_debug_port_register
[2021-May-27 04:22:50] [debug] [Backend] - Select AP 255, DP Bank 0, AP Bank 255
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000)  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.552ms returns -1  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [ info] [Backend] - JLinkARM.dll reported "-1", an unknown error.
[2021-May-27 04:22:50] [debug] [Backend] - ---just_abort_debug_action
[2021-May-27 04:22:50] [ info] [Backend] - Attempting to clear any configuration errors in debug port before closing connection.
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x00, 0x0000001F)  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.475ms returns -1  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_HasError()  
[2021-May-27 04:22:50] [ info] [Backend] - JLinkARM.dll reported "-1", an unknown error.
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] - 0.044ms  
[2021-May-27 04:22:50] [ info] [  JLink] - [Info    ] [JLink     ] JLINK_Close()  
[2021-May-27 04:22:50] [debug] [Backend] - Segger Backend closed.

[Jared]

What voltage do you measure on the RESET, and DEC pins? Measure directly on the pin