Jinx wrote:
>
> > And it's a good idea to use a retriggerable monostable driving
> > a fast switch in the power side of the LEDs.
>
> Nice idea. Next time I do some work on mine I'll try a hack along
> those lines
>
> > Set the mono to about 3x the duty cycle to allow for some
> > margin, and retrigger it with every write to a new column
>
> You should be able to repeatably set the monos timing to within
> a % or two of 1/7th or 1/8th or 1/Xth of the time for a complete cycle
> through the 7 or 8 or X rows, leaving enough time to update the data
>
> It would certainly give better brightness without the need for
> prolonged row driving signals from the PIC

Yes, but if the PIC hangs after the first couple of columns of a 128
column array, a column gets say 125/128 of a 2Amp drive, which will
likely blow it. It's easy enough to trigger the mono from the LSB of
the decoder input so no additional overhead is incurred.

R

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