what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Tue, 21 Sep 2021 08:10:06 GMT

Glad to hear that. What you can do is to "verify" the reply solving your issue so people with a similar issue in the future to find the solution faster. mrono Thank you for a great suggestion as well!

Best regards,

Simon

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Mon, 20 Sep 2021 11:43:00 GMT

Wow, thanks for the suggestion, mrono !

Just tried it out, and it works :-)

Only 1 thing to add: issuing only "R" (for reset) in my case only halts the program (I waited for a while :-). In order to get the output in RTTViewer displayed again, I had to run a "Go" command (CPU starts again):

...
Cortex-M4 identified.
J-Link>R
Reset delay: 0 ms
Reset type NORMAL: Resets core & peripherals via SYSRESETREQ & VECTRESET bit.
Reset: Halt core after reset via DEMCR.VC_CORERESET.
Reset: Reset device via AIRCR.SYSRESETREQ.
J-Link>Go
J-Link>

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Mon, 20 Sep 2021 11:13:16 GMT

Hi, Simon,

I think now all the parts of the problem are clarified :-)

Thanks a lot for the clear explanation !

I now miss the Facebook "Heart" reaction to reply to your support from the beginning of the ticket :-)

Best regards

Mario

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

mrono — Mon, 20 Sep 2021 10:46:04 GMT

[quote userid="75734" url="~/f/nordic-q-a/79140/what-are-the-required-steps-files-definitions-commands-to-get-rtt-output-from-a-custom-app-into-rtt-viewer/330223#330223"]the RTT viewer is disconnected when you do the nrfjprog reset and thus you don't see any further logging information[/quote]

Yes, this is unfortunately true. However, Segger's J-Link Commander can issue a reset without disconnecting the RTT viewer.

So instead of running nrfjprog in a terminal, open J-Link commander and issue a reset there.

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Mon, 20 Sep 2021 10:06:26 GMT

Okay, glad to hear we've resolved one part of the problem then!

Okay, seeing as you're using nrfjprog to do the reset that makes sense. nrfjprog halts the CPU to hijack the debug/trace module and thus disconnect the RTT viewer from the J-Link device. Unfortunately, the RTT viewer does not have the feature that some serial terminals do (like teraterm for instance) where it is able to detect when the COM port is available again and automatically reconnect.

You will either need to do logging over UART (serial) with a terminal that has this feature, or reset the device in your application, either by a button reset or a timeout that resets the device to be able to see the logging behave correctly. It seems like your application runs as intended, but that the RTT viewer is disconnected when you do the nrfjprog reset and thus you don't see any further logging information.

Best regards,

Simon

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Fri, 17 Sep 2021 11:34:55 GMT

Hi, Simon,

thank you for your reply ! It was exactly what I wanted to know and it answers perfectly my original question :-)

[quote userid="75734" url="~/f/nordic-q-a/79140/what-are-the-required-steps-files-definitions-commands-to-get-rtt-output-from-a-custom-app-into-rtt-viewer/329135#329135"]You'll also have to add the nrf_log_backend_rtt.h/.c and SEGGER_RTT.h/ .c files to the project.[/quote]

I think what I was missing and not knowing about was the SEGGER part, because I didn't encounter them when I read about the Logger module in the infocenter, and also because I hadn't seen SEGGER files in the Makefile of the template_project, which I originally started with and used for testing. Many thanks for mentioning them and copying the corresponding required #defines in the sdk_config.h file !

In the meantime I read through the SAADC example too, and I think it helped me get the big picture to a decent extent regarding the use / inclusion of modules :-)

That apart, I couldn't solve my issue with the lack of output after reset :-(

[quote userid="75734" url="~/f/nordic-q-a/79140/what-are-the-required-steps-files-definitions-commands-to-get-rtt-output-from-a-custom-app-into-rtt-viewer/329135#329135"]How exactly do you reset your device on your end?[/quote]

I used the reset command I found in the Makefile under the "flash" recipe, i.e I ran in a Terminal:

nrfjprog -f nrf52 --reset

Could this influence the RTT logging ?

Thanks once again

Mario

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Mon, 13 Sep 2021 06:39:38 GMT

Hi again

I just ran the temperature project on my end to see if I could replicate it, and I see the "Temperature example started" message every time I press the reset pin on my DK. How exactly do you reset your device on your end?

What's necessary to enable the RTT backend on any example should be adding the following defines in sdk_config.h

// <e> NRF_LOG_ENABLED - nrf_log - Logger
//==========================================================
#ifndef NRF_LOG_ENABLED
#define NRF_LOG_ENABLED 1
#endif

// <h> nRF_Log 

//==========================================================
// <e> NRF_LOG_BACKEND_RTT_ENABLED - nrf_log_backend_rtt - Log RTT backend
//==========================================================
#ifndef NRF_LOG_BACKEND_RTT_ENABLED
#define NRF_LOG_BACKEND_RTT_ENABLED 1
#endif
// <o> NRF_LOG_BACKEND_RTT_TEMP_BUFFER_SIZE - Size of buffer for partially processed strings. 
// <i> Size of the buffer is a trade-off between RAM usage and processing.
// <i> if buffer is smaller then strings will often be fragmented.
// <i> It is recommended to use size which will fit typical log and only the
// <i> longer one will be fragmented.

#ifndef NRF_LOG_BACKEND_RTT_TEMP_BUFFER_SIZE
#define NRF_LOG_BACKEND_RTT_TEMP_BUFFER_SIZE 64
#endif

// <o> NRF_LOG_BACKEND_RTT_TX_RETRY_DELAY_MS - Period before retrying writing to RTT 
#ifndef NRF_LOG_BACKEND_RTT_TX_RETRY_DELAY_MS
#define NRF_LOG_BACKEND_RTT_TX_RETRY_DELAY_MS 1
#endif

// <o> NRF_LOG_BACKEND_RTT_TX_RETRY_CNT - Writing to RTT retries. 
// <i> If RTT fails to accept any new data after retries
// <i> module assumes that host is not active and on next
// <i> request it will perform only one write attempt.
// <i> On successful writing, module assumes that host is active
// <i> and scheme with retry is applied again.

#ifndef NRF_LOG_BACKEND_RTT_TX_RETRY_CNT
#define NRF_LOG_BACKEND_RTT_TX_RETRY_CNT 3
#endif

// </e>

// <h> nRF_Segger_RTT 

//==========================================================
// <h> segger_rtt - SEGGER RTT

//==========================================================
// <o> SEGGER_RTT_CONFIG_BUFFER_SIZE_UP - Size of upstream buffer. 
// <i> Note that either @ref NRF_LOG_BACKEND_RTT_OUTPUT_BUFFER_SIZE
// <i> or this value is actually used. It depends on which one is bigger.

#ifndef SEGGER_RTT_CONFIG_BUFFER_SIZE_UP
#define SEGGER_RTT_CONFIG_BUFFER_SIZE_UP 512
#endif

// <o> SEGGER_RTT_CONFIG_MAX_NUM_UP_BUFFERS - Maximum number of upstream buffers. 
#ifndef SEGGER_RTT_CONFIG_MAX_NUM_UP_BUFFERS
#define SEGGER_RTT_CONFIG_MAX_NUM_UP_BUFFERS 2
#endif

// <o> SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN - Size of downstream buffer. 
#ifndef SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN
#define SEGGER_RTT_CONFIG_BUFFER_SIZE_DOWN 16
#endif

// <o> SEGGER_RTT_CONFIG_MAX_NUM_DOWN_BUFFERS - Maximum number of downstream buffers. 
#ifndef SEGGER_RTT_CONFIG_MAX_NUM_DOWN_BUFFERS
#define SEGGER_RTT_CONFIG_MAX_NUM_DOWN_BUFFERS 2
#endif

// <o> SEGGER_RTT_CONFIG_DEFAULT_MODE  - RTT behavior if the buffer is full.
 

// <i> The following modes are supported:
// <i> - SKIP  - Do not block, output nothing.
// <i> - TRIM  - Do not block, output as much as fits.
// <i> - BLOCK - Wait until there is space in the buffer.
// <0=> SKIP 
// <1=> TRIM 
// <2=> BLOCK_IF_FIFO_FULL 

#ifndef SEGGER_RTT_CONFIG_DEFAULT_MODE
#define SEGGER_RTT_CONFIG_DEFAULT_MODE 0
#endif

You'll also have to add the nrf_log_backend_rtt.h/.c and SEGGER_RTT.h/ .c files to the project.

Best regards,

Simon

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Fri, 10 Sep 2021 08:55:33 GMT

Hi, Simon,

thanks for your reply and suggestion !

Just built and flashed the temperature project, with a semi-successful result :-)

The code I used is (I commented out the temperature part and left only the first log output statement with an LED switch-on after it):

// #includes ...
// #defines ...

int main ( void ) {
    nrf_gpio_cfg_output ( LED_PIN ) ;
    
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    NRF_LOG_INFO("Temperature example started.");
    
    nrf_gpio_pin_set ( LED_PIN );
}

The results are as follows:

Setting 1 (sdk_config.h):

NRF_LOG_BACKEND_UART_ENABLED 0

NRF_LOG_BACKEND_RTT_ENABLED 1

NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 1 or 0

NRF_LOG_ENABLED 1

NRF_LOG_DEFERRED 1

No output in RTT Viewer ! --> from what I could read, this can be explained by the fact that I don't have a call to

NRF_LOG_PROCESS() in my code, hence I don't see the output. This is understandable.

Setting 2 (sdk_config.h):

NRF_LOG_BACKEND_UART_ENABLED 0

NRF_LOG_BACKEND_RTT_ENABLED 1

NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 1 or 0

NRF_LOG_ENABLED 1

NRF_LOG_DEFERRED 0

Output in RTT Viewer is shown, but only the 1^st time after a connection is established !

However, no output is shown if the program is for example reset via “nrfjprog -f nrf52 –reset” with a running RTT Viewer connection !

For the output to be shown again, the connection in RTT Viewer must be first disconnected, and then re-established AFTER the chip has been previously reset, e.g.

chip reset
(Connection lost) via File → Disconnect
File → Connect

Output:

00> <info> app: Temperature example started.

00>

i.e. output is shown when:

chip is reset
RTT Viewer is disconnected
RTT Viewer is re-connected anew

Modifying NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLEDas described in:

Link: https://devzone.nordicsemi.com/f/nordic-q-a/46685/no-log-output-to-debug-terminal-in-ses-or-rtt-viewer

does not change the situation !

The only difference is the number of output lines being output in RTT Viewer, i.e.

NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED0

Output:

00> <info> app: Temperature example started.

NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED1

Output:

00> <info> app: Temperature example started.

00>

=> in the 2^ndcase two lines are printed as output, whereas in the 1^stcase only 1 line is printed as output !

Do you know what is the reason for this behavior and what needs to be done to solve it ?

This apart, could you elaborate on:

[quote userid="75734" url="~/f/nordic-q-a/79140/what-are-the-required-steps-files-definitions-commands-to-get-rtt-output-from-a-custom-app-into-rtt-viewer/328821#328821"]actually implement the RTT backend[/quote]

What does it exactly mean to implement the RTT backend ? Could you point me to a resource where all the required steps are described in terms of required headers / sources / Makefile settings / sdk_config.h settings, or alternatively just type them here in as the logging functionality is so fundamental ?

Greets and thanks again

Mario

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Thu, 09 Sep 2021 12:29:28 GMT

Thank you for the thorough answer again. I don't really see any reason that you shouldn't be able to get these messages in the RTT viewer here.

Since yesterday however, I've noticed that the template project doesn't actually implement the RTT backend, so I might be missing a step. What you could do is to try building and running an example that does, like the peripheral/temperature example for instance. Just make sure to set

NRF_LOG_BACKEND_UART_ENABLED to 0 and NRF_LOG_BACKEND_RTT_ENABLED to 1 in the sdk_config.h file. If you still don't see anything in the RTT viewer, try to switch the CR_ON_LF_ENABLED define to 0 in sdk_config.h as well.

Best regards,

Simon

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Wed, 08 Sep 2021 12:33:20 GMT

Hi, Simon,

no issue about the delay, thanks for your new reply.

In the meantime, I somehow managed to get the Debugging in VSCode running via OpenOCD. So, with regard to your last question from your previous reply:

Are you positive that the application runs as intended and actually enters this for loop printing values for you?

I removed the printing loop, and only inserted few NRF_LOG_INFO() lines before switching on an indicator LED to make sure the execution reaches there:

// #includes ...
// #defines ...

int main ( void ) {
    nrf_gpio_cfg_output ( LED_PIN ) ;
    
    ret_code_t err_code = NRF_LOG_INIT ( NULL );
    APP_ERROR_CHECK ( err_code );
    
    NRF_LOG_DEFAULT_BACKENDS_INIT ();
    
    NRF_LOG_INFO ( "1r\n" );
    NRF_LOG_INFO ( "2\r\n" );
    NRF_LOG_INFO ( "3\r\n" );
    NRF_LOG_INFO ( "4\r\n" );
    NRF_LOG_INFO ( "5\r\n" );
    
    nrf_gpio_pin_set ( LED_PIN );   // LED switches on => execution reaches this line ?
}

LED switches on => execution does not break before it. I also stepped the code through in a Debugging session and could step over each NRF_LOG_INFO() call and then finally reached the LED-switch-on code. So, I assume the NRF_LOG_INFO() calls get executed, however no numbers get printed in the RTT Viewer.

I also tried using the JLinkExe together with JLinkRTTClient as described in here:

https://www.justinmklam.com/posts/2019/04/vscode-nrf52/

but still nothing gets printed as with JLinkRTTViewer.

With regard to the connection PCB <--> J-Link, from what I could measure with the multi-meter and by visually inspecting which cable goes where (not everything is visible under the silicon or epoxy or whatever has been applied there + I am kind of only firmware guy with basic hardware skills :-), it must be something like:

https://imgur.com/L7qi8Oa

Is there a reason you've chosen this example project?

Well, currently I have no dev board to experiment with, but only an example device. So, my tasks were:

1st task: make an LED blink (done);
2nd task: get the logs working via RTT (stuck);
3rd task: get readings from the device joystick and get those printed.

So, I am stuck on the 2nd task :-) hence, I can't continue the plan :-(. I received the whole project, and probably by running it I might get RTT output, but if I get it, then I still won't have understood what is going on and required for RTT to work, which I find kind of annoying, because later it might lead to some bug when I do something else. So, the reason to use the very basic template project was just to get started clean, and add functionalities one-by-one when all has worked as expected - I think that is the more decent approach to getting to know something new, as is an nRF52 to me at the present moment.

I will try the UART example as you suggest, but I will be happy to resolve my issue and understand also why it doesn't work and what exactly was missing and required for it to work.

Greets

Mario

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Tue, 07 Sep 2021 08:57:22 GMT

Sorry about the late reply. I've been out of office the past few days.

Can you also explain how the module is connected to the debugging device?

Indeed, the template project is very basic in regards to what is already added to it. Is there a reason you've chosen this example project? We generally recommend starting out with a larger project that's already implemented some of the features you'd already like to use. The peripheral_uart example for instance, uses the RTT backend for logging by default, so you could use that from scratch instead if that's of interest.

Best regards,

Simon

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

boko — Wed, 01 Sep 2021 14:41:42 GMT

How is the connection to the J-Link set up in the RTT Viewer?

- when I run the JLinkRTTViewer from the Terminal I use the following settings (tried also once with the S/N, but same issue, didn't expect to make any difference :-) :

- when I press OK, I get the following output:

in your sdk_config.h file, please make sure that the #define NRF_LOG_BACKEND_UART_ENABLED is set to 0.

I do not have this macro name in my sdk_config.h file ! I read about it in several other posts, but it's just not present.

I am talking about the sdk_config.h file located in /template_project/pca10056/blank/config/sdk_config.h

There are some UART macros which, from the color codes in VScode, I guess are not supposed to be conditionally-compiled, e.g.:

// <e> NRFX_UART_ENABLED - nrfx_uart - UART peripheral driver
//==========================================================
#ifndef NRFX_UART_ENABLED
#define NRFX_UART_ENABLED 1
#endif
// <o> NRFX_UART0_ENABLED - Enable UART0 instance 
#ifndef NRFX_UART0_ENABLED
#define NRFX_UART0_ENABLED 0
#endif

and there some others that, from the the color codes in VSCode again, are to be conditionally-compiled, e.g.

// <e> UART_ENABLED - nrf_drv_uart - UART/UARTE peripheral driver - legacy layer
//==========================================================
#ifndef UART_ENABLED
#define UART_ENABLED 1

or this one

// <e> UART0_ENABLED - Enable UART0 instance
//==========================================================
#ifndef UART0_ENABLED
#define UART0_ENABLED 1
#endif

or this one

// <e> UART1_ENABLED - Enable UART1 instance
//==========================================================
#ifndef UART1_ENABLED
#define UART1_ENABLED 0
#endif
// </e>

or this one

// <e> APP_UART_ENABLED - app_uart - UART driver
//==========================================================
#ifndef APP_UART_ENABLED
#define APP_UART_ENABLED 1
#endif

or these ones

// <e> UART_CONFIG_LOG_ENABLED - Enables logging in the module.
//==========================================================
#ifndef UART_CONFIG_LOG_ENABLED
#define UART_CONFIG_LOG_ENABLED 0
#endif
// <o> UART_CONFIG_LOG_LEVEL - Default Severity level
 
// <0=> Off 
// <1=> Error 
// <2=> Warning 
// <3=> Info 
// <4=> Debug 

#ifndef UART_CONFIG_LOG_LEVEL
#define UART_CONFIG_LOG_LEVEL 3
#endif

So, I do not have NRF_LOG_BACKEND_UART_ENABLED in my sdk_config.h file, but I do have some others whose states are variably either 1 or 0, but I do not know if any of those is meant to exactly correspond to the one you mentioned, i.e NRF_LOG_BACKEND_UART_ENABLED. So, my next question would be if one of those is a substitute for the one you mentioned, or NRF_LOG_BACKEND_UART_ENABLED is just somehow missing in the sdk_config.h file for the template project ?

try to set the NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED define back to 1

I just tried --> no change in the situation :-(

The other thing as feedback: when I flash the program and RTT Viewer is not yet open, the J-Link LED looks as if it is in its heart beat mode. When I then open the RTT Viewer, the J-Link LED starts blinking quite fast, I guess it's the flickering mode, e.g. executing something ?! is it possible that some communication is going on, but I don't see the output ? When I then close the RTT Viewer, the J-Link LED shows steady light for ca. 7 seconds, then I guess its heart beat mode is initiated (as described in the User Manual for J-Link).

Are you positive that the application runs as intended and actually enters this for loop printing values for you?

No, I am not. To be honest I don't know how to make this sure. I am also currently trying to set up the debug configuration in VSCode using the launch.json file, but I have a problem there too, i.e.

Checking target voltage...
Target voltage: 3.30 V
Listening on TCP/IP port 50000
Connecting to target...
Connected to target
Waiting for GDB connection...Restoring target state and closing J-Link connection...
Shutting down...
SERVER CONSOLE DEBUG: onBackendConnect: gdb-server program closed
GDB server exited. Waiting for next server to start...

but I guess I'll need to open another ticket for this issue ...

RE: what are the required steps/files/definitions/commands to get RTT output from a custom app into RTT Viewer ?

Simonr — Wed, 01 Sep 2021 11:35:53 GMT

How is the connection to the J-Link set up in the RTT Viewer?

Also, in your sdk_config.h file, please make sure that the #define NRF_LOG_BACKEND_UART_ENABLED is set to 0. You can also try to set the NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED define back to 1 to see if that helps as well.

Are you positive that the application runs as intended and actually enters this for loop printing values for you?

Best regards,

Simon