On Fri, Aug 15, 2014 at 2:06 PM, Mike Harrison <mike@whitewing.co.uk> wrote=
:
> if you can arrange the right bit rate, you can get one WS2812 bit per 3 S=
PI bits.
> Using a lookup table can reduce the amount of bit-twiddling if necessary.
> Much more efficient on a 16 or 32 bit SPI port but should be doable on an=
 8-bit one if you can get a
> 400ns bit time- not familiar with the PIC18 SPIs but I've done it on a PI=
C32

Hey Mike!

Woah, that's a really cool idea! The PIC18 MSSP does let you specify a
custom divider to generate the bit time. Unfortunately, I believe that
with a 64MHz clock, I'd need a divider of 5.4, to get a clock speed of
2.5MHz. So, conceivably I would probably have to change my chip speed
to make this possible. I'm not sure if this is worth it though. The
nice thing about doing this would be that could send two bits worth of
information per transmission, which would cut the number of interrupts
in half. However, I'd have to lower my clock speed, so I'd get less
instructions between each interrupt.

Any thoughts on the cost vs benefit on this one?

I'm inclined to keep trying ideas based on a 64MHz clock for now, but
to explore this alternate idea perhaps in the future. That said, if
there's something I'm missing, I'm happy to be persuaded otherwise!

Josh
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