Working clock example using 32K watch crystal

[Acetronics2]

Alain,
Darrel's great example uses one crystal mine uses 2. And oh if something is sitting there soldered to the dev board and you don't have code to see if it works!!

Hi, Timc

Lol ... I didn't remember I had modified Darrel's code to use a 32 Khz Xtal ...

and thought it was already done in the original release ...

Here it is.

Alain

[Darrel Taylor]

There's a couple good examples. I like Bruce's.
But it uses in-line assembly language instead of straight PBP.

The Elapsed Timer modification is nice too ... but ...

Nobody wins the LCD's.

[pedja089]

I was playing with TimC RTC code, and I found 1 problem...
If the interrupt occurs between these lines

      GoSub get_time      ' Update minutes and seconds
      TOGGLE LED_0
      LCDOut $fe,2,"Time: ",DEC hours, ":", DEC2 minutes, ":", DEC2 seconds, "   "

There is a chance to show 60 seconds.
It happened to me, so I then wondered what was going on...
Solution:

seconds        VAR BYTE bankA  ' variables within myint must be in bank 0.
minutes        VAR Byte bankA       ' Elapsed minutes
hours          var byte bankA
:
:
:
@myint                  ; create myint label
   TMR1H.7=1
    seconds = seconds+1  ' Increment second
    if seconds > 59 then
        seconds = seconds - 60    ' better then making seconds=0
        minutes = minutes + 1
        if minutes > 59 then
            minutes = 0
            hours = hours + 1
            if hours > 12 then hours = 1    ' simple 12 hour clock format
        endif
    endif 
 PIR1.0=0             ' Clear TMR1 int flag
   @ retfie  FAST

And remove get_time procedure

[pedja089]

I'm trying to add the calendar.
Does anyone have an idea how to make a calculation of leap year.
I tried this
If day>30+month.0 or (Month=2 and day>28 and year//4<>0) or (Month=2 and day>29 and year//4=0)then
month=month+1
but the code is 300b larger then this
If day>30+month.0 or (Month=2 and day>28)then
month=month+1
Is there a more efficient way?

[Ioannis]

How about using 3 If-Then's insead of one with 3 OR's?

Ioannis

[pedja089]

I spent all night trying to find the best way ... I think this is

              If month=2 then
                 If year//4<>0 then
                    DMonth=29
                 else
                    DMonth=28
                 endif
              else
              Dmonth=30+month.0 
              endif   
              If day>Dmonth then
@                CLRF _Day
@                INCF _Month,F
                 If month>12 then

And everywhere there is any = 0, I replaced the @ clrf, +1 replaced with @ incf.
The end result was the RTC which consumes about 2uA and code size about 500B.

[Ioannis]

I think you have to change the <>0 to =0 when you test for the modulo 4.

A better solution to cover more years (you code will not cover year 2100) is to use mod 400, mod 100 and mod 4 to test for leap year (mod 100 is NOT leap year, while 400 and 4 ARE leap years).

Of course we may not live in year 2100, but just in case...

Now about the @ commands, just be sure you are on page 0. Else you have to check the page bits. Or put this subroutine on top of your code.

Ioannis