picaxe 28x1 random number generator

Question

I have some simple code using the random number function from picaxes website (slightly adapted)

symbol counter = b7
symbol randword = b5
for counter = 0 to 10

let randword = timer
random randword

write counter, b5
next counter

end

For some reason on picaxe editor version 5 this works perfectly but on picaxe editor 6 all it does is give out 2's, not very random, I have no idea why.

Any help much appreciated

Thanks

simulation and PICAXE for editor 6 and just simulation for editor 5 at the moment. — pythonstudent, Feb 14 '17 at 16:11
Also, I've added a wait loop which requires you to press a button to start the program so the running time should be random — pythonstudent, Feb 14 '17 at 16:13

score 1 · Answer 1 · answered Feb 14 '17 at 22:39

Checking the PICAXE BASIC language manual shows a few possible problems with your code:

the timer system variable has to be initialised with the settimer command before you can use it
depending on what preload value you use with settimer, the value of timer may well not have changed in the short time between one loop iteration and the next, which will give you the same result from random
random should be used with a word variable (w0, w1, etc) not a byte variable

What I think the manual entry for random is suggesting you should do, although I agree it isn't exactly clear if you're new to random number generation, is to seed random with timer the first time you call it, then seed it with its own previous value each time after that:

symbol counter = b5

let w3 = timer         ; w3 is the word variable consisting of b6 and b7
for counter = 0 to 10

random w3
;  ...do something with the value of w3 (but don't change w3 itself)...

next counter

However after saying all this, it is certainly possible that the simulator in one or other version of the PICAXE Programming Editor doesn't simulate the behaviour of timer correctly in all cases. If you can't get the code working on a real PICAXE, take this question to the PICAXE forum where it will be seen by Revolution Education support staff as well as other knowledgeable users.

picaxe 28x1 random number generator

1 Answers1