Random seed using the ds1307 RTC

**rookie11** · - 25th November 2007, 05:13

Can anyone provide some guidance with those 2 issues I'm having? (number generated is out of my range, and number generated always increasing)

**Darrel Taylor** · - 25th November 2007, 06:39

Maybe this might work ...

A random number is always a word variable.
The value is always between 1-65535.

So if the 1-65535 is considered the Decimal part, then multiplying it times the range you want (in your case 20) and take the High Word result, then add the minimum...

Code:

Value  VAR WORD
RND    VAR WORD
MinCnt CON 10
MaxCnt CON 30
Scale  CON MaxCnt - MinCnt 

RND = 1234 ; The Seed, however you get it

RANDOM  RND
Value = (RND ** Scale) +  MinCnt

**KVLV** · - 25th November 2007, 11:27

Base on Darrel code, this line >>> Scale CON MaxCnt - MinCnt << should be Scale CON MaxCnt - MinCnt +1, so the maximum range will be reached.

Thanks Darrel.

I also attached a little file making a set of 6 random numbers range from 10 to 30 based on Darrel code.