I'm using the nRF52840 DK.
I managed to burn the on-board nRF52840 MCU several times, using the nRF connect windows app.
After several such successful burns, with various test images taken from the SDK, the DK is no longer able to burn the on-board MCU.
The "nRF Connect" fails to connect and read the MCU's flash content, and this is its log:
2019-04-15T07:38:03.032Z INFO Using nrfjprog to communicate with target 2019-04-15T07:41:29.895Z INFO Target device closed.
The log produced by this command: "nrfjprog -e -f nrf52 --log" is this:
2019-Apr-15 10:58:27 -------------------------------------------------------------------------------- 2019-Apr-15 10:58:27 nrfjprog -e -f nrf52 --log 2019-Apr-15 10:58:27 nrfjprog version 9.8.1 2019-Apr-15 10:58:27 -------------------------------------------------------------------------------- 2019-Apr-15 10:58:27 nRF_open_dll 2019-Apr-15 10:58:27 . nRF52_open_dll 2019-Apr-15 10:58:27 . . nRF52_dll_version 2019-Apr-15 10:58:27 nRF_enum_emu_snr 2019-Apr-15 10:58:27 . nRF52_enum_emu_snr 2019-Apr-15 10:58:27 . . nRF52_enum_emu_snr 2019-Apr-15 10:58:27 nRF_enum_emu_snr 2019-Apr-15 10:58:27 . nRF52_enum_emu_snr 2019-Apr-15 10:58:27 . . nRF52_enum_emu_snr 2019-Apr-15 10:58:27 nRF_connect_to_emu_with_snr 2019-Apr-15 10:58:27 . nRF52_connect_to_emu_with_snr 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu 2019-Apr-15 10:58:27 . . nRF52_enum_emu_snr 2019-Apr-15 10:58:27 . . nRF52_connect_to_emu_with_snr 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 7 2019 14:07:15 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: Hardware: V1.00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: S/N: 683138976 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: TELNET listener socket opened on port 19021 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: WEBSRV Starting webserver 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0019ms, 0024ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:016 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: WEBSRV Webserver running on local port 19080 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0022ms, 0027ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:016 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns O.K. 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0025ms, 0030ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:042 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_GetHWStatus(...) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0005ms, 0036ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: There is no generic nRF52 device in J-Link, so we select NRF52832_xxAA. 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:049 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_ExecCommand("Device = NRF52832_xxAA", ...). 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: XML file found at: C:\Program Files (x86)\SEGGER\JLink_V644d\JLinkDevices.xml 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0009ms, 0049ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:052 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: C:\Program Files (x86)\SEGGER\JLink_V644d\JLinkDevices.xml evaluated successfully. 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: Device "NRF52832_XXAA" selected. 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: Device "NRF52832_XXAA" selected. 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0106ms, 0146ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:158 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_ExecCommand("SetRestartOnClose = 0", ...). 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x01 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0000ms, 0148ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:161 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_ExecCommand("DisableFlashDL", ...). 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0001ms, 0151ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:164 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_ExecCommand("SetDbgPowerDownOnClose = 1", ...). 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x01 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0001ms, 0154ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:167 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...). 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0001ms, 0158ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:171 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_TIF_Select(JLINKARM_TIF_SWD) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: returns 0x00 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0003ms, 0162ms total) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: T13BE4 000:175 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: JLINK_SetSpeed(2000) 2019-Apr-15 10:58:27 . . . nRF52_connect_to_emu_without_snr: JLink: (0001ms, 0164ms total) 2019-Apr-15 10:58:27 nRF_read_device_version 2019-Apr-15 10:58:27 . nRF52_read_device_version 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: T13BE4 000:180 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: JLINK_IsOpen() 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: returns 0x01 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: (0003ms, 0168ms total) 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_device 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_device: JLink: T13BE4 000:185 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_device: JLink: JLINK_IsConnected() 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_device: JLink: returns FALSE 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_device: JLink: (0004ms, 0172ms total) 2019-Apr-15 10:58:27 . . nRF52_readback_status 2019-Apr-15 10:58:27 . . . nRF52_is_ctrl_ap_available 2019-Apr-15 10:58:27 . . . . nRF52_read_access_port_register 2019-Apr-15 10:58:27 . . . . . nRF52_coresight_configure 2019-Apr-15 10:58:27 . . . . . nRF52_coresight_configure: JLink: T13BE4 000:193 2019-Apr-15 10:58:27 . . . . . nRF52_coresight_configure: JLink: JLINK_CORESIGHT_Configure() 2019-Apr-15 10:58:27 . . . . . nRF52_coresight_configure: JLink: returns 0 2019-Apr-15 10:58:27 . . . . . nRF52_coresight_configure: JLink: (0103ms, 0276ms total) 2019-Apr-15 10:58:27 . . . . . nRF52_power_debug_and_system_regions 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register: JLink: T13BE4 000:299 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register: JLink: JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000) 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register: JLink: returns -1 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register: JLink: (0004ms, 0280ms total) 2019-Apr-15 10:58:27 . . . . . . nRF52_write_debug_port_register: JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -1. 2019-Apr-15 10:58:27 . . . . . nRF52_power_debug_and_system_regions: JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -102. 2019-Apr-15 10:58:27 nRF_close_dll 2019-Apr-15 10:58:27 . nRF52_close_dll 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: T13BE4 000:309 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: JLINK_IsOpen() 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: returns 0x01 2019-Apr-15 10:58:27 . . nRF52_is_connected_to_emu: JLink: (0003ms, 0284ms total) 2019-Apr-15 10:58:27 . . nRF52_disconnect_from_emu 2019-Apr-15 10:58:27 . . . nRF52_is_connected_to_device 2019-Apr-15 10:58:27 . . . nRF52_is_connected_to_device: JLink: T13BE4 000:315 2019-Apr-15 10:58:27 . . . nRF52_is_connected_to_device: JLink: JLINK_IsConnected() 2019-Apr-15 10:58:27 . . . nRF52_is_connected_to_device: JLink: returns FALSE 2019-Apr-15 10:58:27 . . . nRF52_is_connected_to_device: JLink: (0002ms, 0287ms total) 2019-Apr-15 10:58:27 . . . nRF52_unpower_debug_and_system_regions 2019-Apr-15 10:58:27 . . nRF52_disconnect_from_emu: JLink: T13BE4 000:331 2019-Apr-15 10:58:27 . . nRF52_disconnect_from_emu: JLink: JLINK_Close()
Here is the output of a failed connect attempt via the J-Link commander:
Type "connect" to establish a target connection, '?' for help J-Link>connect Please specify device / core. <Default>: NRF52840_XXAA Type '?' for selection dialog Device> Please specify target interface: J) JTAG (Default) S) SWD T) cJTAG TIF>s Specify target interface speed [kHz]. <Default>: 4000 kHz Speed> Device "NRF52840_XXAA" selected. Connecting to target via SWD Cannot connect to target.