Wednesday, January 21, 2009

2-digit BCD to decimal conversion

Now, I'm working on the full feature clock using DS1307. In the clock, I use many BCD to decimal (bcd2dec) and decimal to BCD conversions for reading and setting time of the DS1307 RTC. MikroC provides buit-in functions for these conversions but the functions consume modest amount of MCU memory space. I have came up with simple functions that consume less memory for doing 2-digit BCD to decimal and the reverse conversions.

2-digit BCD to Decimal conversion function:
unsigned short myBcd2Dec(unsigned short bcd){
return ((bcd >> 4)*10+(bcd & 0x0F));
}

Example: myBcd2Dec(01000101) = 45

2-digit Decimal to BCD conversion function:
unsigned short myDec2Bcd(unsigned short dec){
return (((dec/10)<<4)(dec%10));
}

Example: myDec2Bcd(45) = 01000101
at

3 comments:

  1. UnknownJanuary 22, 2009 at 9:11 PM

    in the code there is not mentionaned any date and time is it?

    ReplyDelete
  2. punkkyJanuary 22, 2009 at 10:08 PM

    No, the code is not the full clock code. It's just the code for 2-Digit BCD to decimal conversion and vise versa. The code for the full working Clock will be posted later as I am working on it.

    ReplyDelete
  3. StuartJune 26, 2012 at 3:54 AM

    Useful code, it helped me check my own version of bcd conversion. But I think there is a typo (missing +) in the dec to bcd version: you shift the tens value right but should then add in the units (mod) value - not multiply.

    ReplyDelete