How to set the date and time to the file on SD card or Flash disk on nRF52840

[Michael Jang]

Hi

I'm trying to file open and write for logging temperature data and others on nRF52840.

I successfully open, read and write on SD card or flash in nRF52840.

I also have used  nrf_cal_set_time(year, month-1, day, hour, minute, second) in nrf_calendar.c successfully.

It's a great and file to display date and time.

But, after file creation using f_open(), f_write() and f_close(), I found that the default date&time of the file is always 01/01/2016.

I appreciate that if you let us know what is wrong from my side and how to change or set the date & time of file property.

Thanks

Minsoo Jang

[Simonr]

Hi

Seems like the time is called from somewhere else in your application, please try finding out where the time is called from, as it doesn't look like GET_FATTIME is able to provide the time of day.

Best regards,

Simon

[Michael Jang]

Hi Simonr

I don't think you understand my situation fully. Sorry for my poor explanation. So, let me explain my program structure one by one.

In brief, I open file and write it to flash memory area on nRF52840 DK

     1. ff_result = f_open(&file, TEMPERATURE_FILE, FA_CREATE_ALWAYS | FA_WRITE);

     2.ff_result = f_write(&file, temper_info, strlen(temper_info), (UINT *) &bytes_written);

     3. file's date is always 01/01/2016

     4. I found that const variable in ffconf.h. see ffconf.h

                            #define _FS_NORTC 1
                            #define _NORTC_MON 1
                            #define _NORTC_MDAY 1
                            #define _NORTC_YEAR 2016

     5. I found that "Timestamp" part in ff.c. See Timestamp in ff.c

                          /* Timestamp */
                         #if _FS_NORTC == 1
                         
                         #define GET_FATTIME() ((DWORD)(_NORTC_YEAR - 1980) << 25 | (DWORD)_NORTC_MON << 21 |                                          (DWORD)_NORTC_MDAY << 16)
                        // #define GET_FATTIME() get_fattime() //Modified 210329
                        #else
                        #define GET_FATTIME() get_fattime()
                        #endif

     6. this has to do with f_open() in ff.c like follwoing. see dw=GET_FATTIME() of f_open() in ff.c

                       

                       FRESULT f_open (
                             FIL* fp, /* Pointer to the blank file object */
                            const TCHAR* path, /* Pointer to the file name */
                             BYTE mode /* Access mode and file open mode flags */
                       )
                       {
                              FRESULT res;

                               .....

                               ....

                    
                        if (res == FR_OK && (mode & FA_CREATE_ALWAYS)) { /* Truncate it if overwrite mode */
                        dw = GET_FATTIME();

                                 ....

     7. It's certain that we have to change  "GET_FATTIME()" in ff.c to set the date and time of opened file

     8. That's reason why I change GET_FATTIME() in ff.c.

                                  f_open() => GET_FATTIME => "#define  #define _NORTC_MON 1 #define _NORTC_MDAY 1                                                                                             #define _NORTC_YEAR 2016"

     9. When I changed GET_FATTIME() in ff.c to  

                                       #define _NORTC_MON 3
                                       # define _NORTC_MDAY 30
                                       #define _NORTC_YEAR 2021

          it works well and successfully. But, the time of the file which is opened and written is always AM 12:00 like

                                        TEMPERATURE_FILE       2021-03-30 AM 12:00 17KB

     10. In conclusion, let me know the way to change the time of file from following '#define' 

           #define GET_FATTIME() ((DWORD)(_NORTC_YEAR - 1980) << 25 | (DWORD)_NORTC_MON << 21 |                                          (DWORD)_NORTC_MDAY << 16) 

            in ff.c because there is no TIME related bit command(there are only YEAR, MON, DAY part).

     

      11. If you can let me know new #define command to set the time of GET_FATTIME(),  I will take care of others         

Thanks 

Michael Jang

[Simonr]

Okay. I think I see now. In our SDK we don't use timestamps in the Fatfs library, and AFAIK we haven't done any testing with these timestamps either. This is an external library, and I have not been able to find where the time of day is set when _FS_NORTC is set to 1, so I'm afraid what help I can provide is rather limited...

From ff.h: If the system does not have an RTC function or a valid timestamp is not needed, _FS_NORTC = 1 is set to disable the timestamp function (so you won't be able to get the current time like this). If _FS_NORTC = 1 all objects will have a fixed timestamp defined by the _NORTC_MON, _NORTC_MDAY and _NORTC_YEAR. To enable timestamp functionalities, the get_fattime() function needs to be added to the project and you'll have to get the current time from a real-time clock.

Best regards,

Simon

[Michael Jang]

Hi Simonr

I got the solution by changing GET_FATTIME()  like following.

Thanks.

 

 #define GET_FATTIME()   ((DWORD)(year - 1980) << 25 | (DWORD)month << 21 | day << 16 | hour << 11 | minute << 5)