RTT Viewer doesn't show any debug messages from nrf52833.

[bini2007]

We use nrf52833 chip but I don't know which SDK and version.

but I used "s113_nrf52_7.2.0_softdevice.hex" in our project having started on 2021.01.27.

So, It's old project starting before.

The problem is as followings:

Our target device is connected with RTT Viewer.

However, RTT Viewer dosen't show any log messages from our target device.

Our project's current configuration for RTT logging are as followings on "sdk_config.h" header file.

1. define belows. 

#define NRF_LOG_ENABLED 1

#define NRF_LOG_BACKEND_RTT_ENABLED 1

2. call on main() function.

NRF_LOG_DEFAULT_BACKENDS_INIT();

Do we have to do more anything for logging on RTT Viewer?

In addition, I attach our "sdk_config.h" file.

Please check it and advice me.

4010.sdk_config.h

[tesc]

Hi,

From what I can tell, the configurations in your sdk_config.h file are good.

I see from your sdk_config.h file that you are also disabling NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED, which is good. Enabling that setting is known to prevent RTT logs from being displayed, at least in the Segger Embedded Studio (SES) debug terminal.

Please note that all settings in sdk_config.h can be overridden, typically through use of an app_config.h file. Please check to see if you have any such overrides, of any of the configs you have mentioned, or of the one I mentioned above. See the SDK configuration header file documentation for details, and in particular the section Overriding the sdk_config.h configuration.

For RTT to work, you must have a debugger connected to your board. Please confirm this is what you do, as well as describe what kind of board you use, how you connect it (physically), as well as all steps and any configurations done with RTT Viewer. Also, please share any errors, warnings or log output provided by RTT Viewer.

For nRF5 SDK based projects, I personally find it the easiest to just start a debug session in SES, for getting the RTT output up and running, as with the RTT Viewer I find it to be slightly more cumbersome to set up. If your project is a SES project, an easy way to check if RTT works from the device point of view is to run a debug session in SES.

Regards,
Terje

[tesc]

Hi again,

Please note also, that in SDK examples the log is initiated at the very beginning of main, typically through a call to the following function (also defined in the main.c of each example.)

/**@brief Function for initializing the nrf log module.
 */
static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();
}

In other words, you should both initiate logging, and initiate the log backends, as well as check the return value of the former.

Regards,
Terje

[tesc]

Hi,

Is your application running successfully, except for getting no logging? For an nRF5 SDK application, you typically need both a SoftDevice and the applicaiton, and if you lack the SoftDevice then the application simply will not run. This might be the issue.

Do you get RTT to work properly with an SDK example, such as e.g. \examples\ble_peripheral\ble_app_hrs when doing the same configuration changes?

Regards,
Terje

[bini2007]

I found missing definition, 

NRF_LOG_USES_RTT used in SEGGER_RTT_Syscalls_GCC.c file.

So I added the definition on our project source.

However, it dosen't work with RTT Viewer via swd.

First of all, we can connect  our target through J-link OB debugger RTT viewer.

The following log says:

LOG: J-Link RTT Viewer V7.94e: Logging started.
LOG: Terminal 0 added.
LOG: Connecting to J-Link via USB...
LOG: Device "NRF52833_XXAA" selected.
LOG: InitTarget() start
LOG: CTRL-AP indicates that the device is secured.
For debugger connection the device needs to be unsecured.
Note: Unsecuring will trigger a mass erase of the internal flash.


LOG: Executing default behavior previously saved in the registry.
LOG: Device will be unsecured now.
LOG: InitTarget() end - Took 230ms
LOG: Found SW-DP with ID 0x2BA01477
LOG: DPIDR: 0x2BA01477
LOG: CoreSight SoC-400 or earlier
LOG: Scanning AP map to find all available APs
LOG: AP[2]: Stopped AP scan as end of AP map has been reached
LOG: AP[0]: AHB-AP (IDR: 0x24770011)
LOG: AP[1]: JTAG-AP (IDR: 0x02880000)
LOG: Iterating through AP map to find AHB-AP to use
LOG: AP[0]: Core found
LOG: AP[0]: AHB-AP ROM base: 0xE00FF000
LOG: CPUID register: 0x410FC241. Implementer code: 0x41 (ARM)
LOG: Found Cortex-M4 r0p1, Little endian.
LOG: FPUnit: 6 code (BP) slots and 2 literal slots
LOG: CoreSight components:
LOG: ROMTbl[0] @ E00FF000
LOG: [0][0]: E000E000 CID B105E00D PID 000BB00C SCS-M7
LOG: [0][1]: E0001000 CID B105E00D PID 003BB002 DWT
LOG: [0][2]: E0002000 CID B105E00D PID 002BB003 FPB
LOG: [0][3]: E0000000 CID B105E00D PID 003BB001 ITM
LOG: [0][4]: E0040000 CID B105900D PID 000BB9A1 TPIU
LOG: [0][5]: E0041000 CID B105900D PID 000BB925 ETM
LOG: RTT Viewer connected

Then, we couldn't see the device logs from our target using RTT viewer.

I guess the conditions goes good a little, however we can't see the logs.

Please advice me.

Thanks,

Jaehong Park

[bini2007]

I tested ble_app_uart, example on nRF53833 DK when I use on SES and RTT Viewer.

The example works well on nRF52833 DK as following SES and RTT Viewer's screenshots.

1. SES

2. RTT Viewer

Then on RTT viewer, it works when I pressed reset button on DK board after connecting nRF SoC using J-link OB. I guess it needs to restart the appllication after connecting to nRF SoC on DK board.

First of all, our target only use 4 pins in swdio, swdclk, Vdd, Gnd.

So, do we have to connect reset pin on our custom target with J-link OB on DK?

and then I mean give the reset signal to our custom target via reset pin after connection with j-link OB.

Please guide us how.

Thanks,

Jaehong Park

[bini2007]

Hi,

I found that there didn't happened on RTT device logs on our target.

When we just download our fw to our custom target via jflash tool, and after reading back on target's memory, it is normal as following screenshot on jflash tool:

Then the next is when reading back on target's memory ,right after attaching by j-link on RTT Viewer.

it is abnormal that our target flash memory was initialize and written in 0xFF ,like erasing memory.

the followings is abnormal screenshot.

I guess I saw the following logs on RTT Viewer.

LOG: CTRL-AP indicates that the device is secured.
For debugger connection the device needs to be unsecured.
Note: Unsecuring will trigger a mass erase of the internal flash.

It was erased because of the above message.

Please check this and inform us why it happened.

Thanks,

Jaehong Park

[bini2007]

Hi,

I found a little solution of this issue.

The next sequence is a small solution of this.

1. Connect target via j-link OB on RTT viewer.

2. Open J-Link.exe CLI program under C:\Program Files\SEGGER\JLink_V812b

3. Connect target via j-link OB on CLI app.

4. input command as "r", "s", "g", "r", "g", etc on CLI app like the attached command.

5. Then we can see the logs from RTT viewer.

The attached command on CLI app.

C:\Program Files\SEGGER\JLink_V812b>JLink.exe
SEGGER J-Link Commander V8.12b (Compiled Jan 15 2025 12:16:22)
DLL version V8.12b, compiled Jan 15 2025 12:15:23

Connecting to J-Link via USB...O.K.
Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jul 24 2017 17:30:12
Hardware version: V1.00
J-Link uptime (since boot): N/A (Not supported by this model)
S/N: 685079944
License(s): RDI, FlashBP, FlashDL, JFlash, GDB
VTref=3.300V


Type "connect" to establish a target connection, '?' for help
J-Link>connect
Please specify device / core. <Default>: NRF52833_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 "NRF52833_XXAA" selected.


Connecting to target via SWD
InitTarget() start
InitTarget() end - Took 3.86ms
Found SW-DP with ID 0x2BA01477
DPv0 detected
CoreSight SoC-400 or earlier
Scanning AP map to find all available APs
AP[2]: Stopped AP scan as end of AP map has been reached
AP[0]: AHB-AP (IDR: 0x24770011, ADDR: 0x00000000)
AP[1]: JTAG-AP (IDR: 0x02880000, ADDR: 0x01000000)
Iterating through AP map to find AHB-AP to use
AP[0]: Core found
AP[0]: AHB-AP ROM base: 0xE00FF000
CPUID register: 0x410FC241. Implementer code: 0x41 (ARM)
Found Cortex-M4 r0p1, Little endian.
FPUnit: 6 code (BP) slots and 2 literal slots
CoreSight components:
ROMTbl[0] @ E00FF000
[0][0]: E000E000 CID B105E00D PID 000BB00C SCS-M7
[0][1]: E0001000 CID B105E00D PID 003BB002 DWT
[0][2]: E0002000 CID B105E00D PID 002BB003 FPB
[0][3]: E0000000 CID B105E00D PID 003BB001 ITM
[0][4]: E0040000 CID B105900D PID 000BB9A1 TPIU
[0][5]: E0041000 CID B105900D PID 000BB925 ETM
Memory zones:
  Zone: "Default" Description: Default access mode
Cortex-M4 identified.
J-Link>s

****** Error: CPU is not halted
J-Link>r
Reset delay: 0 ms
Reset type: NORMAL (https://wiki.segger.com/J-Link_Reset_Strategies)
Reset: Halt core after reset via DEMCR.VC_CORERESET.
Reset: Reset device via AIRCR.SYSRESETREQ.
J-Link>s
00000A80:   06 4B              LDR       R3, [PC, #+0x18]
J-Link>g
Memory map 'after startup completion point' is active
J-Link>s

****** Error: CPU is not halted
J-Link>r
Reset delay: 0 ms
Memory map 'before startup completion point' is active
Reset type: NORMAL (https://wiki.segger.com/J-Link_Reset_Strategies)
Reset: Halt core after reset via DEMCR.VC_CORERESET.
Reset: Reset device via AIRCR.SYSRESETREQ.
J-Link>g
Memory map 'after startup completion point' is active
J-Link>

after input command on CLI app, RTT viewer give up device logs as following screenshot:

Anyway, we started a little more for fixing this issue.

Then, I guess RTT viewer grabbed and held the booting start of device.

Please advice us how to fix it.

Thanks,

Jaehong