how to set real time and get the current time reading

[young]

I am think a project that people setup time year, month day, hour, minute and second and then run the program the program will save this data as well as other measuring data to a storage. I am wondering how to build the system. any help please

[Ttelmah]

It will depend massively on how much data is involved. Obvious solution is a battery backed RTC chip like the DS1302. You can set this, and it will keep time for you, sending an interrupt to the main processor at intervals. You then take the other measurements, and put the lot into another storage device (EEPROM for small amounts, up to CF, for large amounts of data).

Best Wishes

[Guest]

Did exactly what Ttelmah mentioned and use a DS1302 for the clock with a super cap for backup power when the board wasn't plugged in. Stored time-stamped temperature data on EEPROM - several days of data can be stored even if you take samples every several seconds. I calculated that using 4 big EEPROMS (512K bytes each), you could store data (two bytes) every minute for weeks. I really didn't need the exact time, but used the DS1302 so the user could select the sampling interval - every minute, hour, 15 seconds, etc...