Multiple Timing Cycles 16F877A

[TedO]

Hi Guys

I have been requested by my friend to design a refrigeration controller for him. The main program that controls the compressor etc is straightforward, as a relatively newbie to Flowcode V6, what I am struggling with is the defrost timer and defrost heater cycles as there are 4 defrost timing cycles that can be selected and 4 defrost heater cycles that work in conjunction with the defrost timer. Only 1 defrost timer and 1 defrost heater DIP switches will be selected at any one time.
I am thinking of using a 16F877A chip with an LCD display and also an 8 pin DIP switch to select the defrost timer/heater cycles as follows: Switch 1-4 Defrost Timers 4, 6, 8 and 12 Hours, Switch 5-8 Defrost Heater Cycles 15, 25, 35 and 45 Minutes. The reason being that one can "tune" the defrost timer and defrosting heater to the best suited selections for optimum operation.
The compressor also has a 5 minute "delay ON" timer when activated by the temperature sensor, so as you can see, it becomes a bit scary!

I have tried different methods to be able to have a "master" timer that I can tap into according to the 2 selected DIP switches and compressor delay, but alas it has failed dismally.

Any ideas would be appreciated as I am not fully up to speed with interrupts and the like yet.

Regards
Ted

[Steve001]

Hi Tedo

Have you seen this post re timer settings

viewtopic.php?f=54&t=17496

Steve

edit :- this post may be useful also

http://www.matrixtsl.com/blog/setting-rtc-in-a-flash/

If you search for RTC there is quite a lot of information on this

[TedO]

Hi Steve

Thanks for the info, will check it out.

Regards
Ted