Flickering too much

Ramboman

I am working on a flickering ball, 12cm dia, with 40 bi-color leds.
Half the ball is ready for testing.
Leds are multiplexed in a separate cog with pub "mux"
"Main" set leds on and off randomly.
I expected leds to flicker one at a time on and off.
In the reality, all the leds are flickering at the same time, being randomly off, red, green and sometimes yellow.
I don't understand why all the leds are flickering; it's nice, but it's not logic (for me).
If somebody can help !
Thanks

Mike Green

1) Your stack may be too small. I'd suggest one at least 20 levels, maybe more.

2) It's a small point, but you might want to initialize the column output bits to 1s like "OUTA[noparse][[/noparse]8..12]~~"

Ramboman

Thanks Mike for such a prompt anwer.

I followed your suggestions with no change to the flickering.

I changed "mpx" frequence from 100 to 1000, that solved the problem, but I don't understand why?

I guess there must be some interference between COGs; what's yout feeling about?

Regards

Graham Stabler

The mpx frequency must be high enough that you don't notice it is being multiplexed, you were probably seeing the multiplexing. Trying setting all leds on and running the multiplexing at the lower frequency and see what you get.

Graham

Ramboman

Hi Graham,
you are right, at freq 1000 I don't notice flickering. At 100 I do.
But following mpx, it should lid one led at a time; in fact, they are flickering all together???
Rgards
Roland