ETH LwIP program runs only when debugging

[TonyRuan]

Hello ST Community!

I have a problem and I need your help. I have searched and read most of the related articles but couldn't find a solution! I am using:

• Hardware: Nucleo H755 board connected directly to the computer.
• Software: STM32CubeMX version 6.12 and MDK-ARM compiler version 5.41

I have carefully read the article: https://community.st.com/t5/stm32-mcus/how-to-create-a-project-for-stm32h7-with-ethernet-and-lwip-stack/ta-p/49308 and some other related tutorials, as well as related comments. I have followed the following steps.

1. Configure according to the instructions for CM7 core, no RTOS used.
2. Generate code (MDK Toolchain; min version 5.32).
3. Add MX_LWIP_Process to the main loop.
4. Compiling with the option [ARM Compiler: Use default compiler version 5] results in an unusually very slow compilation time.
5. Compile with option [ARM Compiler: Use default compiler version 6] then compile time is normal but there is an error: ../Middlewares/Third_Party/LwIP/system\arch/cc.h(50): error: 'sys/time.h' file not found

I have fixed this error according to: https://github.com/STMicroelectronics/STM32CubeF4/issues/29 specifically:

• In file cc.h, line 43:

#if defined (GNUC) & !defined (__CC_ARM)

is corrected to

#if defined (GNUC) && !defined (__CC_ARM) && !(defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 6010050))

• In file lwip.c, line 25 and 178,

#if defined ( __CC_ARM )

is corrected to

#if defined (__ARMCC_VERSION) && (__ARMCC_VERSION >= 6100100)

And then, I compile and there is a warning in the ethernetif.c file, line 124: __attribute__((section(".Rx_PoolSection"))) extern u8_t memp_memory_RX_POOL_base[];

I corrected it to

__attribute__((section(".Rx_PoolSection"))) u8_t memp_memory_RX_POOL_base[];

extern u8_t memp_memory_RX_POOL_base[];

6. In the Scatter file I added the content for RW_DMARxDscrTab, RW_DMATxDscrTab and memory_RX_POOL_base

7. Compile successfully without error and warning

8. Download program to MCU, check ping from PC and get the result: Destination host unreachable.

9. Enter debug mode, press Run (F5) 3 time, the program runs and pings from PC successfully: bytes=32 time=1ms TTL=255.

I set the breakpoint at the beginning of the main function, I have to press the Run button 3 times before the cursor stops at this breakpoint.

10. If I press the hard reset button or turn off the power, the program does not run.

Please show me my mistakes and how to fix them! I'm a newbie. Thank you very much!

[Guillaume K]

Typically this happens when the application tries to use C library functions (like printf()) that use semi-hosting.

Semi hosting requires the debugger to do some actions like getting the string from the MCU (through debugger link) and printing it in the IDE .

When running without the debugger, the project must be compiled without semi hosting.

one possible way on MDK-ARM to disable semi hosting is to select "Use micro-lib" in "code generation" in Target tab of your project config.

The C library "micro-lib" doesn't use semi hosting. The printf() won't work.

Another way would be to replace the standard library functions with one that doesn't use semi hosting.

[Guillaume K]

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@TonyRuan wrote: 4. Compiling with the option [ARM Compiler: Use default compiler version 5] results in an unusually very slow compilation time.

On MDK-ARM compiler 5 , it is the generation of code browsing information that takes time. To disable it, you can uncheck "Browse information" in Output tab of your project config.