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jdcowpland
jdcowpland
Associate III
January 31, 2014
Question

f_utime

  • January 31, 2014
  • 19 replies
  • 4232 views
Posted on January 31, 2014 at 09:31

Anyone got any experience using the f_utime function from chan's fatfs? I've got a function that uses it to put a timestamp on a file I create on an SD card, but it returns INVALID_NAME every time. Not quite sure why. Anybody have any ideas? (Btw, I'm using a STM32F415VG if that helps). My code looks like this: 

FRESULT set_timestamp (char *obj)
{
FILINFO fno;
RTC_TimeTypeDef RTC_TimeStructure;
RTC_DateTypeDef RTC_DateStructure;
RTC_GetTime(RTC_Format_BIN,&RTC_TimeStructure);
RTC_GetDate(RTC_Format_BIN,&RTC_DateStructure);
int hour = RTC_TimeStructure.RTC_Hours;
int min = RTC_TimeStructure.RTC_Minutes;
int sec = RTC_TimeStructure.RTC_Seconds;
int month = RTC_DateStructure.RTC_Month;
int mday = RTC_DateStructure.RTC_Date;
int year = RTC_DateStructure.RTC_Year;
year+=2000;
fno.fdate = (WORD)(((year - 1980) << 9) | month << 5 | mday);
fno.ftime = (WORD)(hour <<11 | min <<5 | sec/2 );
return f_utime(obj, &fno);
}

#fatfs
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19 replies

chen
chen
Associate II
January 31, 2014
Posted on January 31, 2014 at 10:13

Hi

Do you have a working real time clock?

The code needs to be able to read the time from a RTC.

Your code shows calls to a RTC but is there a RTC in your system?

Is it set correctly?

jdcowpland
jdcowplandAuthor
Associate III
January 31, 2014
Posted on January 31, 2014 at 11:53

Yes RTC is working. I can debug and hover over the values and it shows me the current time without any problems.

chen
chen
Associate II
January 31, 2014
Posted on January 31, 2014 at 12:21

Hi

OK, looking at your code the other thing to look at is the input to your function ''* obj''

Is it null by any chance?

It is suppose to be the path - as a string.

jdcowpland
jdcowplandAuthor
Associate III
January 31, 2014
Posted on January 31, 2014 at 13:35

Ah ok that might be where I'm going wrong. I'm creating a file using this code: 

res = f_mount(SD, &fs32);
res = f_open(&fil, Filename, FA_CREATE_ALWAYS | FA_WRITE);
res = f_write(&fil, SmartBuffer, size, &BytesWritten);
res = f_close(&fil);

and then trying to give it the timestamp by calling my function: 

res = set_timestamp(&fil);

But based on what you're saying, I should be calling it as 

res = set_timestamp(Filename);

right?
jdcowpland
jdcowplandAuthor
Associate III
January 31, 2014
Posted on January 31, 2014 at 13:35

Ah ok that might be where I'm going wrong. I'm creating a file using this code: 

res = f_mount(SD, &fs32);
res = f_open(&fil, Filename, FA_CREATE_ALWAYS | FA_WRITE);
res = f_write(&fil, SmartBuffer, size, &BytesWritten);
res = f_close(&fil);

and then trying to give it the timestamp by calling my function: 

res = set_timestamp(&fil);

But based on what you're saying, I should be calling it as 

res = set_timestamp(Filename);

right?
chen
chen
Associate II
January 31, 2014
Posted on January 31, 2014 at 15:14

Hi

''But based on what you're saying, I should be calling it as 

res = set_timestamp(Filename);

right?'' Yes, make sure the filename is drive:path\filename. Drive should be the same as what fatfs uses
Tesla DeLorean
Tesla DeLorean
Guru
January 31, 2014
Posted on January 31, 2014 at 15:27

Without spending a lot of time digging through the documentation, I would expect the f_utime() to work on correctly pathed and closed files. Observe if any errors are returned.

But, more specifically if you properly implement your RTC abstraction in diskio.c (get_fattime), you probably would have to play game later with setting the creation/modification time stamps.
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jdcowpland
jdcowplandAuthor
Associate III
January 31, 2014
Posted on January 31, 2014 at 16:09

Great thanks! works now. Quick question on another fatfs issue. I have SD and USB set up for fatfs and they both work, but I have to mount and dismount each one each time I want to change. This seems to take quite a while to do and I was wondering if you know if it's necessary to do that or if there's a way to keep both mounted. I tried using f_chdrive, but didn't seem to work.

Tesla DeLorean
Tesla DeLorean
Guru
January 31, 2014
Posted on January 31, 2014 at 16:37

I haven't spent any time doing so, but FatFs seems to intrinsically support multiple drive through the diskio.c abstraction. I would assume you'd f_mount() to a different drive and memory context once for each and open files respectively with ''0:xyz'' , or ''1:abc'' type

http://elm-chan.org/fsw/ff/en/open.html
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jdcowpland
jdcowplandAuthor
Associate III
February 3, 2014
Posted on February 03, 2014 at 11:40

Ah yeah, thanks! turns out I was using the fatfs from 2011 so was getting a bit confused with the documentation! Any idea how to access a directory within a directory? i.e., say I wanted to open a folder in the path ''0:dir1/dir2''. I've tried using f_opendir and f_chdir, but each time it comes back saying no path. It's happy with ''0:dir1'' for opendir, or with ''/dir1'' for chdir, but can't seem to get it to go into the next directory.

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