topic Re: BCD to Binary in 8-bit Microcontrollers

BCD to Binary

PabloA — Wed, 06 Jun 2007 20:28:13 GMT

Hi every body!.

I include in my proyect a Real Time Keeper that give me all time data in BCD format and I need to store data in a RAM Buffer that is addressed with the hour data, but I can't use BCD format to address.

So any body know any way to convert BCD format to Binary? I need to convert BCD to binary from "0" to "23".

Thanks you for your interest.

Pablo.

Re: BCD to Binary

bigmac — Wed, 06 Jun 2007 21:26:40 GMT

Hello Pablo,

Assuming "packed BCD" format, with both decimal digits contained within the same byte, here is a possible C function -

byte BCDconvert (byte BCDval)

{

return (((BCDval & 0x30) >> 4) * 10 + (BCDval & 0x0F));

}

Here is the same process written in assembler -

BCDconvert:

lda BCDval

and #$30

nsa

ldx #10

mul

psha

lda BCDval

and #$0F

add 1,sp

ais #1 ; Adjust stack pointer

rts

; On exit, ACC contains the binary value

Regards,

Mac

Re: BCD to Binary

PabloA — Wed, 06 Jun 2007 23:32:50 GMT

Dear Mac:

I work perfectly. Just what I need.

Thank you.

Best regards.

Pablo