Facing memory access related issues on STM32F767VIT6 board

[rdb]

I am encountering a memory access issue in my application, which runs on Azure RTOS on a custom STM32F767VIT6‑based target board. The application receives JPEG images from an MQTT broker via the EC200U modem, using USART on the board.

The problem arises when I declare a global array of size 180 KB to store the image. Even though I initialize this array with valid non‑zero content (JPEG image data in hex), the debugger consistently shows all zeros when I attempt to read it.

Interestingly, when I reduce the array size to 100 KB, the behavior is normal — the data is correctly written and read. I am using the ST‑Link 2.0 debugger from STMicroelectronics, and the project is built in STM32CubeIDE.

Since my JPEG images can be as large as 180 KB, I need to resolve this memory limitation. Could you provide detailed guidance on the root cause of this issue and possible solutions? I have attached my workspace in .7z format for reference.

[MHoll.2 · Accepted solution]

Apart from the fact that the attached workspace did not compile.

You have:

image_buffer[] defined in app_netxduo.c as c

char image_buffer[IMAGE_BUFFER_SIZE_CAM] = {0};

but used in ImageTransferThroughSIM.c as 

extern char image_buffer[IMAGE_BUFFER_SIZE];

IMAGE_BUFFER_SIZE_CAM seams to be 1024*1

while 

IMAGE_BUFFER_SIZE is 1024*100

[rdb]

Thanks for the quick and detailed reply.

I’ve attached the updated project, which now resolves the earlier compilation errors and the buffer size mismatch, you had mentioned in your reply. Could you review it to check for any remaining memory‑mapping issues or other potential problems that might explain the unusual behavior I’m seeing? In particular, I’ve noticed that IP address acquisition occasionally fails, and I’d like to confirm whether this is related to the way I’ve structured the project.

Thanks & Regards,

[MHoll.2]

This is a new problem please marke this topic as resolved an open an new one.