On Thu, Dec 11, 2008 at 4:17 PM, Michael Hennebry <[email protected]> wrote: > On Thu, 11 Dec 2008, Steve Franks wrote: > >> Anyone successfully done an spi slave on a tiny2313? This unbuffered >> shift register is junk. I can't seem to empty it fast enough at 8MHz, >> even removing all my debugging statements from mainloop, and running >> the spi master at 100kHz, and reseting the edge counter on every >> rising edge of CS. Enough time debugging. Time to use the uart >> instead... > > It seems that the slave could use more time *between* bytes. > What happens if the SPI clock rate is F_CPU/6 > and the time between bytes is 200 cycles? > What is the slave CPU frequency? Are you sure?
I assume you're exactly correct. I just moved things over to a spare uart and it was working in about 5 minutes, so I'll probably just avoid the SPI on the 2313 in the future. I have been developing a theory lately that bosses are generally sold on the "software is cheap and flexible" idea, so everything's supposed to be done in software. However I've found I then often spend days fixing things with software that could be fixed with a couple wires or a different chip in the hardware in about 15 minutes. What this generally means in practice is to buy a much bigger processor than you need, so you're not fooling around with stuff like this ;) Even the mega4/8/168 has a "real" spi interface on it, I believe. Should've rtfm before I picked the part, I assumed the SPI core was the same on all AVR's, that's all. Steve _______________________________________________ AVR-chat mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/avr-chat
