Software Real-Time Clock on HC12

I suggest you setup a heartbeat interrupt - say 5ms or 1ms, depending on the granularity you need - and do the time maintenance therein.

Steve

if (RTC_tick>= XX ){ seconds++; RTC_tick = 0;

if (seconds>=60){ minutes++; seconds = 0; } if (minutes>=60){ hours++; minutes = 0; } if (hours>=24){ days++; hours = 0; } }

You have to define XX based on the heatbeat time you setup. Eric

With "heartbeat" do you mean using the real-time interrupts? If so, it would be best if I could set it up such that it is called every second to increment the clock.

I also found someone suggesting to use the pulse-width modulator, but I am unsure as to how to do that.

Getting out the HC12 data sheet again...

I mean use one of the timers to generate a regular interrupt.

If your only realtime requirement is updating the clock, then sure. But one often needs to have finer time control than 1s.

Errrr.... PWM is not directly appropriate. However the timer may well be a potential interrupt source.

Good plan ;).

Steve

Looking at the data manual finds the Clock Generation Module, Realtime Interrupt. Interrupts occur at one of eight program-selectable rates in binary fractions of oscillator frequency. Use a power-of-two oscillator and you can get exact time-of-day; otherwise, throw in a fudge factor from time to time.