Hi, I am trying to make a timer where you can store 7 days of ON/OFF times. I have simulated the code & it works fine. The problem is keeping the time right. If I use 32.768kHz as an Oscillator + DT_INT on timer 1, very soon the time goes out of sync, because of the instructions in the main program & also in INT routine.
I am considering using DT_INT on external INT, and generate 1 sec pulses on PortB.0 using 555 timer IC.
I would like to know if someone has had the same thought or if there is any other cheaper way to overcome this problem, I don't want to go for expensive RTC ICs.