DS1337 - 12h to 24h mode

[lerameur]

Hello,

I am trying to convert from 12h mode to 25H mode and vice versa with a Ds1337 chip. Not getting great results for now.

What I understand Bit 5 and 6 or the hours plays a role in converting. Her is a clip from the datasheet:
The DS1337 can be run in either 12-hour or 24-hour mode. Bit 6 of the hours register is defined as the 12- or 24-
hour mode-select bit. When high, the 12-hour mode is selected. In the 12-hour mode, bit 5 is the AM/PM bit with
logic high being PM. In the 24-hour mode, bit 5 is the second 10-hour bit (20–23 hours).
I am configuring it so that when two buttons are pressed down for over 1.5 seconds, the conversion between 12h mode to 24h mode is done. From what I understan, I also need to convert the time myself example: from 20H to 8H. The code for me should work but keeps giving me random values, any ideas ?
thanks

        If (PortC.5 = 1) & (PortC.6 = 1) then Pause 1500
	     If (PortC.5 = 1) & (PortC.6 = 1) then
            'IF hourly mode = AM
            I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]  
            Pause 10
                 if RTCHour.6 = 1 then      'turn into 24h mode   therefore 1 to 11 converts to 13 to 23
                 point =2
                 gosub bcd_to_bin
                 RTCHour = TempVal + 12 
                 RTCHour.6 = 0
                 endif
                 if RTCHour.6 = 0 then      'turn into 12h mode   therefore 13 to 23 converts to 1 to 11
                 point =3
                 gosub bcd_to_bin
                 RTCHour = TempVal - 12 
                 RTCHour.6 = 1
                 endif
            I2cwrite SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour] 
            Pause 100
          endif

[Tabsoft]

I could see a couple of issues here, but without additional information it's a guess.

1. You do not post your RTC Initialization routine so how are you setting up the RTC 12 Hour or 24 Hour mode initially?
1a. After initialization does your project display the correct values before you enter your 12/24 Hour configuration routine?

Note: If you change the 12/24 hour mode at any time with a write to the RTC, you will need to perform a second write to the RTCHour register (noted in the DS Pg 9 last paragraph under "Clock and Calendar").

2. I see that you are looking at the 12/24 hour bit, but I do not see that you are checking/setting the AM/PM bit (RTCHour.5). When the RTC is set for 12 hour mode you might want to set this or the calendar values of the RTC will be off.

3. You did not include your bcd_bin routine so there may be issues there, can't tell without seeing it.
3a. You seem to be converting from BCD to BIN (gosub bcd_bin) when you read and are wanting to change to the other mode (12/24 Hr) but...
I do not see where you are converting from BIN back to BCD before you write back to the RTC.
Unless you are using the "point" variable in a IF/Then or Select Case structure in the bcd_bin routine to select BcdToBin or BinToBcd, again hard to tell without seeing the code. I also assume the TempVar variable holds the converted value from the bcd_bin routine??

Also, if you are using and LCD or other output device, try and display out the variables at different stages of your configuration routine to make sure that the values are what you expect.

Perhaps you might want to post more of your code to see if we can help further.

Just my thoughts.

Regards,

[richard]

I think your becoming a good case for the snippets are us award
but if you intention is to just to set/reset 24 h mode on the chip

 If(PortC.5 = 1) & (PortC.6 = 1) then Pause 1500
  If (PortC.5 = 1) & (PortC.6 = 1) then
   'IF hourly mode = AM
   I2CRead SDApin,SCLpin,$D0,$02,[RTCHour]  
   RTCHour.6 = ! RTCHour.6
   I2cwrite SDApin,SCLpin,$D0,$02,[RTCHour]     
  endif
 endif

[lerameur]

Here is the full code.
The display gosub is not being used, will be used when display in a 7 segment display.
Now I am using a LCDout command to view my numbers

'////////////////////////////////////////////////////
'////////////////// PROGRAM /////////////////////////
'////////////////////////////////////////////////////
 I2CWRITE SDApin,SCLpin,$D0,$00,[$56,$59,$20,$00,$00,$00,$00,$00] ' Write to DS1337 to initialize RTC 
 pause 10
             I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]     ' bit 5 of hour is 1 for PM  , 0 for AM
             pause 10
             'RTCHour.5 = 1      'bit 5 is the AM/PM bit with logic high being PM   AND NOT USED
            ' RTCHour.6 = 0   '24h selected    ' for 12 or 24 h  mode ,  when high 12h mode is selected
             'in 24 hour mode (=0)  bit 5 is used for hours 20 to 23
             
                  I2CwRITE SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]  
                   pause 10
                       
Mainloop:
        I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]  
        gosub bcd_to_bin 
        
        If (PortC.5 = 1) & (PortC.6 = 1) then Pause 1500
	     If (PortC.5 = 1) & (PortC.6 = 1) then
            'IF hourly mode = AM
            I2CRead SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour]  
            Pause 10
                 if RTCHour.6 = 1 then      'turn into 24h mode   therefore 1 to 11 converts to 13 to 23
                 point =2

                 RTCHour.6 = 0
                 endif
                 if RTCHour.6 = 0 then      'turn into 12h mode   therefore 13 to 23 converts to 1 to 11
                 point =3
                 RTCHour.6 = 1
                 endif
            I2cwrite SDApin,SCLpin,$D0,$00,[RTCSec,RTCMin,RTCHour] 
            Pause 100
          endif
   
        temp1_min = RTCMin_temp1  
        m = temp1_min
        'PortA.0 =1
        'gosub display 
      '  PortA.0 =0
        
        temp2_min = RTCMin_temp2  
        n = temp2_min
      '  PortA.1 =1
      '  gosub display 
     '   PortA.1 =0  
         
        temp1_sec = RTCSec_temp1  
        o = temp1_sec
       ' PortA.2 =1
       ' gosub display 
       ' PortA.2 =0
        
        temp2_sec = RTCSec_temp2  
        p = temp2_sec
       ' PortA.4 =1
        'gosub display 
        'PortA.4 =0

        		lcdout $FE,1, "Time: ",  HEX2 RTCHour, ":", hex2 RTCmin ,":", HEX2 RTCsec 'in decimals... wow
				lcdout $FE,$C0, dec TempVal , " :" ,dec RTCHour_temp1,":", dec RTCHour_temp2,":", dec point
				Pause 150 
				
    goto Mainloop
    end

    bcd_to_bin:
                  
     if (RTCHour.6 = 1 ) then      'bit 5 is used if RTCHour.6 = 0   ; 24h selected
       RTCHour.6 = 0
       RTCHour.5 = 0
     RTCHour_temp2 = $0F & RTCHour
     RTCHour_temp1= RTCHour >> 4 
     endif
     if (RTCHour.6 = 0 ) then 
     RTCHour_temp2 = %00001111 & RTCHour
     RTCHour_temp1= RTCHour >> 4                        ' Shift down four to read 2 BCD value
     TempVal = RTCHour_temp1 * 10 + RTCHour_temp2       ' this calculate the hours in decima
    
      if ( TempVal > 19 ) then 
            return
        else 
         RTCHour.5 = 0
         RTCHour_temp2 = $0F & RTCHour
         RTCHour_temp1= RTCHour >> 4 
         endif
      endif
         
     RTCMin_temp2 = $0F & RTCMin               ' Clear off the top four bits
     RTCMin_temp1= RTCMin >> 4                       ' Shift down four to read 2 BCD value
     
     RTCSec_temp2 = $0F & RTCSec                     ' Clear off the top four bits
     RTCSec_temp1= RTCSec >> 4                       ' Shift down four to read 2 BCD value

    return

[richard]

this may be better

If(PortC.5 = 1) & (PortC.6 = 1) then Pause 1500
  If (PortC.5 = 1) & (PortC.6 = 1) then
   'IF hourly mode = AM
   I2CRead SDApin,SCLpin,$D0,$02,[RTCHour] 
   temp1 = ((RTCHour>> 4) * 10) + (RTCHour& $0f)    , to binary

   if RTCHour.6=1  then   ' 12h mode 
        if RTCHour.5=1then  temp1=temp1+12  ' pm
   
   else  
         if temp1 > 12 then
         temp1=temp1-12
   endif

  rtcHOUR = ((temp1 / 10) << 4) + (tEmp1 // 10)  ' to bcd
  

 RTCHour.6 = ! RTCHour.6  '  set/reset   24h mode

   I2cwrite SDApin,SCLpin,$D0,$02,[RTCHour]     
  endif
 endif

[richard]

no I'm still wrong, why is time so complicated

try

	
	
If(PortC.5 = 1) & (PortC.6 = 1) then Pause 1500
  If (PortC.5 = 1) & (PortC.6 = 1) then
   I2CRead SDApin,SCLpin,$D0,$02,[RTCHour]
  if RTCHour.6=1 then
       temp1 = (((RTCHour&$1f)>> 4) * 10) + (RTCHour& $0f)    ' to binary  mask off am/pm
     else
       temp1 = ((RTCHour>> 4) * 10) + (RTCHour& $0f)    ' to binary
     endif
   if RTCHour.6=1  then   ' 12h mode 
        if RTCHour.5=1then  temp1=temp1+12  ' pm
   
   else  
         if temp1 > 12 then
         temp1=temp1-12
   endif

  rtcHOUR = ((temp1 / 10) << 4) + (temp1 // 10)  ' to bcd
  

 RTCHour.6 = ! RTCHour.6  '  set/reset   24h mode

   I2cwrite SDApin,SCLpin,$D0,$02,[RTCHour]     
  endif
 endif

[lerameur]

Hi Richard,

Trie both code with same error,
It does seem to go from 19h to 7h.
When I attempt to go back to 19H I get a four appearing before the hours .. like so : 7:01:01 to 47:01:01 then the four disappear to come back to 7:01:01 ( yes minutes and seconds are still incrementing. But this is weird that the four would just leave by its own !

Also the datasheet specifies that the bit 5 hour.5 is used for the hours between the 20 to 23 hours.

[richard]

the "4 " probably comes from the fact that temp1 is used in you display routine and its getting messed with by my code

make a new byte var temp12 for use in the 12/24 routine in place of temp1


but it should go to 19h not stay at 7h check if the am/pm is getting cleared when 24h mode is selected
I have to go to work for a while