binaris - decimalis szubrutin

[HWSW Famulus]

> A kovetkezo kodolasra nem tud valaki egy binaris - decimalis
> atalakito szubrutint? PIC16fxxx-hez kellene,
> Ketto regiszter lenne a bemenet es X regiszter lenne a kimenet.
>
> Internally, this calculation is performed by the DS1624 to provide
> 0.03125 C resolution.
> The temperature reading is provided in a 13 bit,
> two s complement reading by issuing READ TEMPERATURE command.
> Table 2 describes the exact relationship of output data to measured
> temperature.
> The data is transmitted serially through the 2 wire serial interface,
> MSB first.
> The DS1624 can measure temperature over the range of -55 C to +125 C
> in 0.03125 C increments. For Fahrenheit usage a lookup table or
> conversion factor must be used.
>
> TEMPERATURE/DATA RELATIONSHIPS Table 2
> TEMP         DIGITAL OUTPUT (Binary)    DIGITAL OUTPUT (Hex)
> +125C       01111101 00000000          7D00h
> +25.0625C   00011001 00010000          1910h
> +0.5C       00000000 10000000          0080h
> +0C         00000000 00000000          0070h
> -0.5C       11111111 10000000          FF80h
> -25.0625C   11100110 11110000          E6F0h
> -55C        11001001 00000000          C900h
>
> --
> udv.:
> jozsi


Nekem a google azt adta ki pl....

KJ
--------------------------
Format of Temperature Data.

The temperature data is returned as two bytes. The first byte, T.BYTE1 
contains the whole part in degrees C. The highest five bits of the second 
byte, T.BYTE0 consists of the fractional part. This is the number of 0.03125 
degrees C.

For example, consider;

     0001 1001      0001 0000

     whole part     fract part in upper 5 bits
     = 16 + 8 + 1   = 2 * 0.03125
Thus the temperature is 25.0625 or 25.06.
Thus the fractional portion may be calculated;

     T_FRACT_100 = ((T.BYTE0 >> 3) * 312) / 10
Thus, the temperature could be then displayed as;
     DEBUG DEC T.BYTE1, ".", DEC T_FRACT_100, CR
Note that the most significant bit of T.BYTE1, is a sign bit; 0 indicates 
positive and 1 indicates negative. Thus, if negative, the two's compliment 
of the result must be taken.
For example;

          1110 0110 1100 1000

Ones Comp 0001 1001 0011 0111
Twos Comp 0001 1001 0011 1000
Thus the whole part is 16+8+1 or 25. The fractional part is 0.03125 * 
(4+2+1) or 0.22 degrees C. Thus, the result is -25.22 degrees C.
This may be implemented;

     IF (T.BIT15 <> 0) THEN MINUS

     T_FRACT_100 = ((T.BYTE0 >> 3) * 312) / 10
     DEBUG DEC T.BYTE1, ".", DEC T_FRACT_100, CR
     GOTO CONTINUE

MINUS:
     T = ~T + 1          ' perform two's complement
     T_FRACT_100 = ((T.BYTE0 >> 3) * 312) / 10
     DEBUG "-", DEC T.BYTE1, ".", DEC T_FRACT_100, CR
     GOTO CONTINUE

CONTINUE: