What is "flush buffer" in mmc used for ?

[husam]

Hi,
I'm new to MMC & SD, and I hope for some help !!!

1- What is "flush buffer" in mmc used for ?

2- I use mmcsd.c library from CCS PCWHD compiler and I saw a
function called:

[asmallri]

I have not used the driver you are using but I can guess these.

When you write to an SD/MMC card you write in 512 byte blocks. What actually happens when you write to the file system the write takes place into the file buffer, not the physical media. When the file buffer is full, or you attempt to write to a different sector, or you close the file then the driver writes (flushes) the buffer to the media. However, if you have an application that only writes a few bytes at a time (say a GPS at 10 second recording intervals) you don't want to lose data that is in the buffer when you turn off the GPS without closing the file. Periodically "flushing" the file system will write the current buffer to the media.

A write_byte() function would write a single byte to the file buffer.
A write_block() function would write a sequence (block) of bytes to the file buffer.
_________________
Regards, Andrew

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