AZURE RTOS Filex - how to access second volume on a SD card using FILEX

Question

AZURE RTOS Filex - how to access second volume on a SD card using FILEX

SQ Jin 16

Two volumes are created on a SD card, the file system is exfat. Then I put some files to partition and try to read files using filex. Now i can access to first volume, but i cannot find a service to read the files on second volume.

QuantumCache 20,681 Reputation points Moderator

2022-01-27T23:56:50.207+00:00
Hello @SQ Jin Thanks for posting this query on this forum!

What was th command you have used for first volume and is there any error you may add to this query?

fx_directory_first_entry_find

Gets the first directory entry.

UINT fx_directory_first_entry_find( FX_MEDIA *media_ptr, CHAR *return_entry_name);
SQ Jin 16 Reputation points

2022-01-28T01:43:38.787+00:00

here is my code

169263-read-files.txt
and result:
attributes | size | file short name | file long name
volume 0 VOLUME01
directory 0 System Volume Information
file 44234 03alarm.wav
file 191086 04stop.wav
file 184320 audio.wav
file 32428 00run.wav
file 5291086 01run2.wav
SD card available size -- 10222MB
SD card available size -- 10222MB

I entered debug mode and confirmed sdio_disk.fx_media_number_of_FATs is 2.
QuantumCache 20,681 Reputation points Moderator

2022-01-28T08:20:24.14+00:00

Thanks for the quick reply, we are looking into it!

1 answer

Your answer

QuantumCache 20,681 Reputation points Moderator

2022-01-27T23:56:50.207+00:00

Hello @SQ Jin Thanks for posting this query on this forum!

What was th command you have used for first volume and is there any error you may add to this query?

fx_directory_first_entry_find

Gets the first directory entry.

UINT fx_directory_first_entry_find( FX_MEDIA *media_ptr, CHAR *return_entry_name);
SQ Jin 16 Reputation points

2022-01-28T01:43:38.787+00:00

here is my code

169263-read-files.txt
and result:
attributes | size | file short name | file long name
volume 0 VOLUME01
directory 0 System Volume Information
file 44234 03alarm.wav
file 191086 04stop.wav
file 184320 audio.wav
file 32428 00run.wav
file 5291086 01run2.wav
SD card available size -- 10222MB
SD card available size -- 10222MB

I entered debug mode and confirmed sdio_disk.fx_media_number_of_FATs is 2.
QuantumCache 20,681 Reputation points Moderator

2022-01-28T08:20:24.14+00:00

Thanks for the quick reply, we are looking into it!

Answer 1

Hi @SQ Jin , the fx_media_open function opens one volume each time. The number of FATs does not mean volume count. The second volume needs to be opened by calling fx_media_open too.
In current sample drivers, only the first partition is accessed. See the code in the driver:

        status =  _fx_partition_offset_calculate(media_ptr -> fx_media_driver_buffer, 0,  
                                                 &partition_start, &partition_size);

The driver reads partition 0 info only. To enable access to the second partition, you can modify the driver to support multiple partition access. Besides, you need to pay attention to thread safety issues as the driver may be called from different threads simultaneously.

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AZURE RTOS Filex - how to access second volume on a SD card using FILEX

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