RANDOM and 12F683 - generates same values each time

[CuriousOne]

include "modedefs.bas" 
DEFINE OSC 4
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 1
DEFINE LCD_BITS 4 
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 1500
DEFINE LCD_DATAUS 44
ADCON1=%00000110 'CONFIGURE PORT A AS DIGITAL

PIRVELI VAR BYTE   'CHARTVISAS BEEPEBIS RAODENOBA
MEORE VAR BYTE      'CHARTVISAS LEDEBIS CIMCIMIS RAODENOBA
MESAME VAR BYTE     'meore etapisatvis shemtxveviti ricxvi
MEOTXE VAR BYTE     'MESAME ETAPIS SHEMTXVEVITI RICXVI
DROEBITI VAR WORD   'DROEBITI SHEMTXVEVITIS GENERACIISATVIS
DROEBITI2 VAR WORD
DROEBITI3 VAR WORD
MTVLELI VAR WORD    'VARIABLE FOR COUNTER
bvar1 var byte
bvar2 var byte
ROM1    VAR BYTE
ROM2    VAR BYTE
ROM3    VAR BYTE
ROM4    VAR BYTE

'PRAVI VAR GPIO.0

'DEFINITIONS
TAVKA:
DROEBITI2=0
DROEBITI3=0
DROEBITI=0
READ 1,ROM1
READ 2,ROM2
READ 3,ROM3
READ 4,ROM4



GENERATE: 'CVLADEBIS GENERACIA
RANDOM DROEBITI
PIRVELI=(DROEBITI//6)+1
RANDOM DROEBITI
MEORE=(DROEBITI//6)+1
RANDOM DROEBITI
MESAME=(DROEBITI//6)+1
RANDOM DROEBITI
MEOTXE=(DROEBITI//6)+1

lcdout $fe,$c0,"1=",#pirveli, "  2=",#meore, "  "
pause 50
goto generate
end

On each cycle run, it returns different results. With 12F683, results are fixed, does not changing, no matter how many times loop is run.

[HenrikOlsson]

I may be misunderstnading but previously you said that you needed some random numbers on power up. Now you're running the routine in a loop (at least that's how I understand it) - that's not the same thing. Each time thru the loop the seed will be what the last RANDOM statement generated. But when you start from scratch (ie power up) the seed will always be 0. As long as the seed is the same (ie 0 at power up) you'll get the same results - and I'll stick to that for a little while longer ;-)

Run this on a 16F870 and on a 12F683

GENERATE: 'CVLADEBIS GENERACIA
  RANDOM DROEBITI
  PIRVELI=(DROEBITI//6)+1
  RANDOM DROEBITI
  MEORE=(DROEBITI//6)+1
  RANDOM DROEBITI
  MESAME=(DROEBITI//6)+1
  RANDOM DROEBITI
  MEOTXE=(DROEBITI//6)+1

  lcdout $fe,$c0,"1=",#pirveli, "  2=",#meore, "  "
  pause 50
end

Cycle the power and run it again. Does it really give you A) Random numbers on the 16F870 but not on the 12F683 and/or B) Different results on 16F870 compared to the 12F683?

/Henrik.

[CuriousOne]

Tested the above code. On power up, it gives 3 and 6 on 16f870 and 2 and 4 on 12f683, same results on each power up.

however, if I place it in the loop, results on 16f870 are changing, while on 12f683 they remain 2 and 4.

[HenrikOlsson]

Hi,
OK, the fact that you don't get the exact same sequence from the two devices could possibly (I don't know) come from the different instruction width (12 vs 14 bits) between the two. But why the 12F683 doesn't continue the sequence when the routine is looped is beyond me.

/Henrik.