Auto update Real time with Ds1302?

[lambk89]

Hi All!
I use DS1302 to read time. But i want to auto update time when my circuit start but not setup time.
Please tell me can i do it?
Thanks?

[Ttelmah]

Just call rtc_init, then read the time with rtc_get_date & rtc_get_time.

Provided the battery backup is correctly attached, the chip will have kept running. You'd ll need a way to call rtc_set_datetime, at some point when you _do_ want to adjust the date and time.

Look at the example ex_rtc.c
This does exactly this. You sit in a loop waiting for either 'S' (to set/change), or 'D' (to display the time). Wake it up, use 'S' to set the clock, then power the PIC down. Then re-power it, and use 'D'. You will see the clock still running counting from the value you set when you typed 'S'.