Shiftin with external Clock howto ?

[Charles Linquis]

If you run an 18F at 40Mhz, you can decode that in software. If you don't need to do anything else at the same time, it is easy. But
if you have to read continuously while you are doing something else, then I would recommend making friends with someone who can write you an ISR in ASM.

[Charles Linquis]

I have been doing some timing. You can, indeed get into- and out of, an ASM interrupt in about 12 uSec (18F @ 40Mhz), so that is a viable solution. A PBP ISR takes about 25, so that wouldn't work.