On Sat, 3 Dec 2016 22:38:38 +0000, Tim Watts wrote:

I wonder how practical that would be - bit banging at 400kHz (is that
right - it's been a while?) - seems a pretty realtime operation for a
full on OS like linux (unless you actually use RT features or write it
as a kernel driver or something???

Out there some where is some code for bit banging on an aurdino. The
core is a bit of assembler that untilises the known number of clock
cycles per instruction to get the timing right. IIRC that assembler
is called as an interupt service routine. Getting the interupt rate
right might be tricky on a Pi as the clock isn't fixed.

--
Cheers
Dave.