How random is "RANDOM"?

[RussMartin]

I'd like to get a better feeling for how random the result from RANDOM is. Any comments?

[tenaja]

IIRC, it repeats every 65,000 times.

[skimask]

IIRC, it repeats every 65,000 times.

IF you use the same seed value every time, yes, it repeats the same sequence every 65535 time.
However, whenever I'm using RANDOM, I use a whatever 16-bit I have free as the seed value. That works as long as I'm not grabbing the 16-bit timer value at the same exact time every time.

[mister_e]

http://www.picbasic.co.uk/forum/showthread.php?t=7555&

If you want something really random... white noise generator fed to an internal PIC counter + using a random sampling time... even the white noise generator with Count would probably do.

Tons of way to Fry and egg
Tons of way to Skin a Cat
Every road leads to Roma

Choose the one who fits your local expression

[RussMartin]

I guess my question was a little broad. Let me refine it.

For example, were I to generate random intervals between 1 and 10 seconds long (inclusive) doing this:

             SEED=32771
LOOP:  	RANDOM SEED
	TIME=(SEED//10)+1
	TIME=1000*TIME
   	HIGH LED        	
       	PAUSE TIME		
             LOW LED         	
       	PAUSE 1000		
             GOTO LOOP		
             END

. . . can I expect the distributions to "look" really random? (In 100 loops, can I expect to see about 10 of each value in each category of 1 second, 2 seconds . . . 10 seconds, etc.?) And, in the sequence, will I see a discernable pattern?

In some small BASIC implementations, I've had to do the equivalent of this:

             SEED=32771
LOOP:  	RANDOM SEED
	TIME=(SEED//11)+1
	IF TIME<2 OR TIME>10 THEN GOTO LOOP
	TIME=1000*TIME
   	HIGH LED        	
       	PAUSE TIME		
             LOW LED         	
       	PAUSE 1000		
             GOTO LOOP		
             END

. . . in order to get good distributions of small numbers.

[mister_e]

Probably you'll have better results if you change the SEED value.