Turning semihosting ON

[abhipray]

I am having a hard time turning ON semihosting. Here's my setup:

- Debugging is done via Eclipse GDB SEGGER J-Link Debugging with the Enable Semihosting checked and console route to both Telnet and GDB Client. 

- Code is linked with --specs=rdimon.specs

When I run the the debugger, and break at the printf/fprintf/puts, the step-into calls are skipped. The Eclipse semihosting window does not display anything.

Any ideas on what could be going wrong? 

[abhipray]

Just a follow up, I am taking the blinky example and making the changes described here: https://mcuoneclipse.com/2014/09/11/semihosting-with-gnu-arm-embedded-launchpad-and-gnu-arm-eclipse-debug-plugins/. i.e

- Adding LDFLAGS += --specs=rdimon.specs -lrdimon
- Removing -lnosys
- Calling initialise_monitor_handles() first thing in main

[Håkon Alseth]

Hi,

 

If you're having issues with semihosting, I'd recommend that you look into using RTT instead, which others users also have done:

https://devzone.nordicsemi.com/f/nordic-q-a/7930/using-semihosting-to-printf

 

Since the above thread was solved years ago, we have added full support for RTT as backend in nrf_log module (also supports UART as a backend). You can enable RTT by setting define sdk_config.h::NRF_LOG_BACKEND_RTT_ENABLED to '1'. 

By default, UART is the backend used, so you should disable that in the same header file, by setting define NRF_LOG_BACKEND_UART_ENABLED '0'.

 

Note: Eclipse supports RTT https://mcuoneclipse.com/2015/07/07/using-segger-real-time-terminal-rtt-with-eclipse/

 

Kind regards,

Håkon

[abhipray]

Thanks for your response. I am aware of RTT and we are already using it for logging purposes. I am interested in getting semihosting setup in order to use an existing utility that makes use of semihosting (gprof as explained here: https://mcuoneclipse.com/2015/08/23/tutorial-using-gnu-profiling-gprof-with-arm-cortex-m/). I could rewrite the profiler code to output data over RTT but I was hoping that setting up semihosting was going to be straightforward. Do you have any tips on debugging semihosting? or would you recommend the RTT route?

[Håkon Alseth]

How does your various settings look?

It is important that the GDB executable is set properly in "GDB Client setup", as shown in the first image in this post:

https://devzone.nordicsemi.com/f/nordic-q-a/15253/debugging-problem-with-gnu-arm-eclipse-toolchain-nrf52-blinky/58241#58241

Note that this one is for semihosting + SWO, so you should not enable SWO in your case.

 

I haven't tried that tutorial using gprof, so I am not able to say if this will work with our devices or not (with projects using the SoftDevice)

 

Best regards,

Håkon