RTOS/F28M35H52C: SYSBIOS FatFS implementation with external SPI flash: filesystem overhead ?

Ril Dank

Part Number: F28M35H52C
Other Parts Discussed in Thread: SYSBIOS

Tool/software: TI-RTOS

Hello,

I don't know if you guys can help but I thought I'd still ask here.

Hi, I just implemented the diskio layer for sysbios FatFs for a 16Mbit (2MBytes) flash memory (SST26x16B over SPI). The memory has a total of 512 sectors of 4 kBytes each.
Everything is working fine except after formatting the device(FDISK), there is only 51 clusters of free space remaining (from f_getfree).
On my FS, 1 cluster = 1 sector = 4096 Bytes.

Is it possible that the overhead of the FS is so big (90% in this case)?

Thanks for the help!

Ril

over 8 years ago

0 ToddMullanix over 8 years ago

TI__Guru* 96960 points

Hi Ril,

That seems too high. Are you using this on the C28 or the M3? Have you looked at this example: processors.wiki.ti.com/.../TI-RTOS_Examples_SerialFlash ?

I'll brush it off and see how free space it has.

Todd

0 Ril Dank over 8 years ago in reply to ToddMullanix

Intellectual 455 points

Hi Todd, thanks for answering.

This is on the M3 spi3 interface.

Actually I think I know my mistake... I've changed sector size _MAX_SS in ffconf.h from 512 to 4096 (factor 8) but I haven't recompiled the library...
It's still working but I'm using only 1/8 if each sector. So 51x8= 408 remaining free sectors sounds like a more reasonable result.

Does that make sense ? Is it normal that I'm getting this result if the library has not been recompiled ?

Thanks a lot,

Ril

0 ToddMullanix over 8 years ago in reply to Ril Dank

TI__Guru* 96960 points

Yes, you need to rebuild FatFS if you change this value.

Todd

0 Ril Dank over 8 years ago in reply to ToddMullanix

Intellectual 455 points

Thanks for your help:)

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RTOS/F28M35H52C: SYSBIOS FatFS implementation with external SPI flash: filesystem overhead ?