Electrical – How to write data to end of line of existing file (STM32CubeMX FATFS SDIO issue)

fatsdiostm32stm32cubemx

I have successfully coded write data into a CSV file is an SD card using STM32 CubeMS FATFS SDIO interface 1-bit mode.

But I can't find the file append function in HAL FATFS driver to write data to existing file. Is there another way to do this using STM32CubeMX and HAL drivers?

Best Answer

Exactly as you would on other platforms.

Open the file for append

The f_open() function has a FA_OPEN_APPEND flag, which makes subsequent f_write() functions to append data at the end of the file.

Move the file pointer to the end of the file

If the file can't be opened in append mode (e.g. when existing data must be accessed first), then you can set the file pointer to the length of the file.

f_lseek(fp, f_size(fp));

Related Solutions

Electronic – arduino – ATMEGA328P SPI MMC/SDIO

As you point out, there are SDIO cards available with various useful functionality. This should tell you that it is possible to produce an SDIO slave device. If you can find an SDIO slave interface IC, or a microcontroller with an SDIO interface that can be configured as a slave, or if you can write an HDL well enough to build an SDIO slave interface in an FPGA, then you have a shot at doing this.

More broadly, I suggest that you explain what it is you're actually trying to do. Doing so may elicit an approach that is practical and that you haven't thought of.

Electrical – STM32F7 FATFS and SD card Write problems

Try moving this part:

for(j = 0; j < 640; j++) { 
    if((j%2) == 0) 
        img_buf[j] = 0xfb54; 
    else 
        img_buf[j] = 0xF7E0; 
}

To the position immediately before the SD_Mount() call at the top. If this doesnt work, comment out the error-checking IF blocks (after your f_writes) and try again. Underrun usually means the TX fifo buffer isnt getting filled fast enough with data, so this might be a solution.

Best Answer

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Electronic – arduino – ATMEGA328P SPI MMC/SDIO

Electrical – STM32F7 FATFS and SD card Write problems

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