Hey Folks,
Description:
I am using STM32N6570-DK with Azure RTOS (ThreadX + FileX) to store camera frames on an SD card using SDMMC2.
Use case:
Capture camera frames (RGB565, 320×240) using DCMIPP
Display frames via LTDC
Continuously write frames to SD card using fx_file_write()
Issue:
Small file read/write (text file) works correctly.
When continuously writing video frames (~153 KB per frame), FileX fails after 2–3 frames.
FileX returns FX_IO_ERROR (144).
Failure occurs during media flush / directory update, not directly in application code.
Configuration:
From fx_stm32_sd_driver.h:
#define FX_STM32_SD_DMA_API 1
#define FX_STM32_SD_CACHE_MAINTENANCE 0
#define FX_STM32_SD_MAX_TRANSFER_SECTOR 16
#define FX_STM32_SD_DEFAULT_SECTOR_SIZE 512
FX_STM32_SD_WRITE_CPLT_NOTIFY() waits on a ThreadX semaphore.
SDMMC2 interrupt enabled.
GPDMA interrupts currently not enabled.
NVIC priority for SDMMC2 was initially 0
Additional Observations:
Indicates possible DMA/cache/interrupt contention between:
SDMMC2
Camera (DCMIPP)
LTDC
Questions:
For STM32N6 + FileX + SDMMC2, when FX_STM32_SD_DMA_API = 1:
Is GPDMA mandatory?
Which GPDMA IRQs must be enabled?
If SD driver uses polling or IT mode, should FileX still wait on a semaphore in
FX_STM32_SD_WRITE_CPLT_NOTIFY()?
Is there a recommended maximum sector count per SD write for STM32N6?
Are there recommended NVIC priorities for:
GPDMA
DCMIPP / LTDC
when using ThreadX + FileX?
Is there any reference design for high-throughput SD writes (video logging) on STM32N6?
NOTE: Any Assistance will be appreciable.....
Thankyou.
Best Regards,
Aashritha
