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Multi-part logic......

 
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JAM2014



Joined: 24 Apr 2014
Posts: 138

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Multi-part logic......
PostPosted: Mon Apr 16, 2018 4:22 pm     Reply with quote
Hi All,

I'm trying to code a test for dates that fall within a certain date range, but a simple & obvious method is defying me at the moment.

Let's suppose I want to find out if a specific date falls between two end point dates, say March 11th & Nov. 4th. I've been able to code a test that works for the beginning date or the end date separately, but I haven't been able to combine them into a working piece of code that tests both date limits! Argh!!!

Here is a test program that I'm trying to make work!

Code:

#include <18F44K22.h>
#fuses INTRC_IO, NOWDT, PUT, NOLVP, NOPBADEN, FCMEN
#use delay(clock=8000000) 

#define PWR_LED Pin_B1
#define Serial_TxD Pin_B4   // serial debug port

#use rs232(baud=9600, xmit=Serial_TxD, stream = Diag)

void main()
{
   int8 iIndex;

   signed int8 UTCOffset = 0;
   unsigned int16 iMonth = 0;
   unsigned int16 iDay = 0;
   unsigned int8 iDayMax = 0;

   // Here we turn off the Pwr LED
   output_low(PWR_LED);
   delay_ms(500);

   // Here we blip the Power LED at power-up to show that the Lighting interface is working
   for ( iIndex = 0 ; iIndex < 3 ; iIndex++ )
   {
      output_high(PWR_LED);
      delay_ms(250);
      output_low(PWR_LED);
      delay_ms(250);
   }
      
   // Here we leave the Power LED ON
   output_high(PWR_LED);

   for (iMonth = 1; iMonth <= 12; iMonth++)
   {

      switch (iMonth)
      {
         Case 1:
         Case 3:
         Case 5:
         Case 7:
         Case 8:
         Case 10:
         Case 12:
         iDayMax = 31;
           break;

         Case 2:
         iDayMax = 28;
         break;

         Case 4:
         Case 6:
         Case 9:
         Case 11:
         iDayMax = 30;
         break;
      }

      for (iDay = 1 ; iDay <= iDayMax ; iDay++)
      {

         //Here we do the UTC offset correction!
         if (((((iMonth >= 3) && (iDay >= 11)) || (iMonth > 3))) && ((((iMonth <= 11) && (iDay <= 4)) || (iMonth < 11))))
            UTCOffset = -4;
         else
            UTCOffset = -5;

         fprintf(Diag, "Month: %Lu  Day: %Lu  UTCOffset: %d\n\r", iMonth, iDay, UTCOffset);
        }      

   }

   while(1){}

}


Any input on the proper test I need to be performing to make the this code work as intended?

Thanks!

Jack

Last edited by JAM2014 on Tue Apr 17, 2018 2:01 pm; edited 1 time in total
temtronic



Joined: 01 Jul 2010
Posts: 9246
Location: Greensville,Ontario

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PostPosted: Tue Apr 17, 2018 5:37 am     Reply with quote
Code:

//function to decide if DST or EST
void dst_calc() {
if((rtcdow==0) && (rtcmth==3)&&(rtcday>=8)&&(rtcday<=16)&&(rtchrs==0)&&(rtcmin==0)&&(rtcsec==0)&&(dstflg==0))
{
rtchrs=rtchrs+1;
//ds3231_set_date_time(rtcyer,rtcmth,rtcday,rtcdow,rtchrs,rtcmin,rtcsec);   //spring ahead !
dstflg=1;
lcd_gotoxy(15,2);
printf(lcd_putc,"DST");
//add rtc eeprom saving here !
}
else if ((rtcdow==0) && (rtcmth==11)&&(rtcday>=1)&&(rtcday<=8)&&(rtchrs==00)&&(rtcmin==0)&&(rtcsec==0)&&(dstflg==1))
{
rtchrs=rtchrs-1;
//ds3231_set_date_time(rtcyer,rtcmth,rtcday,rtcdow,rtchrs,rtcmin,rtcsec);   //spring ahead !dstflg=0;
dstflg=0;
lcd_gotoxy(15,3);
printf(lcd_putc,"noDST");
//add rtc eeprom storing here !
}


variables rtcxxx are the data from the rtc module,dtslfg is the daylight savings time flag.


OK, here's a quick cut and paste from my chickencoop project
It ain't pretty but I'll get back to it AFTER I get 'sunset' to be correct.
Got 18/4/13 to be correct( 20:00 instead of -4:00) by changing the 'loop' that put hrs within 0 to 24) but it fails around day 160ish..sunset at -3:00 !

Jay
JAM2014



Joined: 24 Apr 2014
Posts: 138

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PostPosted: Tue Apr 17, 2018 2:08 pm     Reply with quote
Hi All,

I needed to get away from this problem for a while to clear my head and be able to 'see the forest thru the trees'! Anyway, I've got the code working, and I've updated the original post with working code!

I haven't done much time/date arithmetic, but it always seems to be pretty gnarly!

Thanks,

Jack
temtronic



Joined: 01 Jul 2010
Posts: 9246
Location: Greensville,Ontario

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PostPosted: Tue Apr 17, 2018 7:25 pm     Reply with quote
yes, you can lose a LOT of sleep over 'time math' ! Back when RAM and EPROMs were pricey, I figured out how to store time in 1 byte. As long as you're OK with 15 minute 'intervals', you can do it in 7 bits, leaving a bit to be the 'control' bit to turn a device on or off. Being one byte makes 'time math' a lot easier and faster,especially when using PICs !
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