UART example with external toolchain breaks debugging with "Stopped by vector catch"

[devCheek]

I'm working in Segger Embedded Studio and NRF52840-dk. The project is configured to work with External Toolchain -> Arm Gnu Embedded Toolchain (9 2020-q2-update).

I've imported the complete UART example from the Nordic SDK folder. If I start debugging, while APP_UART_FIFO_INIT(), JLINK stops with following message: "Stopped by vector catch".

The application stops in startup_armcm-gcc.S at "Default_Handler: b"

I expect, that I need to assign a handler for e.g. NMI_HANDLER.

Sorry for this maybe nooby question - I'm literally lost.

Appreciate any help, thanks and cheers

[devCheek]

Maybe one remark: I'm able to receive the first char over serial connection but no more

[Jared]

Hi,

 A vector catch would indicate that the there is an exception thrown somewhere. 

Sorry for this maybe nooby question - I'm literally lost.

Is there a specific reason for why don't use the toolchain offered by SES? I would just recommend to either use SES as it is, or use a text editor such as VS Code with GCC. We already have examples that can be built with GCC and makefiles

regards

Jared

[devCheek]

Hi Jared,

Thanks for the fast response. I needed to use a more recent compiler than available because of other software parts.

I choose to use SES because of other projects in the team going on, using SES. But I'll try to switch to VSC.

Here's the part of the disassembly:

--- startup_ARMCM_GCC.S -- 181 -----------------------------
.thumb_func
.weak NMI_Handler
NMI_Handler:
b .
    E7FE        b 0x00000186 <NMI_Handler>
--- startup_ARMCM_GCC.S -- 186 -----------------------------
Default_Handler:
b .
    E7FE        b 0x00000188 <UsageFault_Handler>
    BF00        nop
--- nrf_gpio.h -- 487 --------------------------------------

In my startup_ARMCM_GCC.S, I defined

def_irq_handler    NMI_Handler

[Jared]

Hi,

devCheek said:

In my startup_ARMCM_GCC.S,

 Does this indicate that you're not using the included startup files? 

Honestly, I would just recommend using the gcc with the makefiles that are already included in the example folder in the SDK, if that is an option. I don't really have much experience with using the external toolchain option in SES. Maybe the community does?

regards

Jared

[devCheek]

Thanks for the feedback. I was able to solve the problem now.

Maybe some chronological background for others facing the same problem:

• I followed the tutorial to use an external toolchain in SES, created a new project, adapted the toolchain and compiler settings etc.
• With this new project, a new startup file has been generated (which I used)
• I was able to build an empty "hello-world" project.
• I added the sdk, application code and includes from the peripheral/uart example in the sdk folder. Then the described problem occured.
  
  
• After trying different solutions, I started to suspect the startup file to be the problem.
• I copied the startup file from the uart SES example project in the sdk, which didn't help.
• I swapped back to the generated Startup file, copied in all interrupt handler definitions from the example project - but it didn't help.
• It was really strange. I added interrupt handlers for 43 interrupts, but it always stopped with "Default Handler", I wasn't able to handle any interrupts.

Solution: I removed all statrtup files and added the specific startup file from the CMAKE folder of the example application.

I'd really like to know, which exact part went wrong / was wrongly configured. I expected to get a working configuration using the "new external build executable" wizzard and handling all interrupts.

Thanks Jared for the great and fast support.

Best regards