Just wondering what folks' opinions are on the default clock rate and frequency for P2 programs. On P1 a lot of programs ended up using 115_200 baud and 80 MHz. Early P2 development tools either defaulted to this (p2gcc) or used 230_400 and 160 MHz (fastspin). That was fine for development, but now that we've got (approximately) final hardware and we've seen that things are stable at a higher clock frequency, I wonder if we should establish a kind of informal convention for baud rate and clock. It would just be a convention, of course -- particular applications may have particular requirements on clock frequency or baud, and naturally they'll use whatever is appropriate. But it would be convenient if the tools and terminal emulators defaulted to some widely used values.
Here are some thoughts on baud rates:
115_200: matches common P1 baud rate, but is slow
230_400: double P1 rate, so convenient, and good for bit-banging. But slow for file transfers and such.
921_600: I think some terminal programs max out at this. Decent speed
2_000_000: max that the ROM bootloader supports?
921_600 seems like a good compromise between speed and widespread support. OTOH for tools like loadp2 that we have control of perhaps 2_000_000 is better, especially if we're doing things like serving files or doing TCP/IP over serial. The only drawback of these higher speeds would be that bit-banged serial becomes tricky, but honestly for P2 people should be using the smart pins for serial I/O so I think that's a very minor consideration.
For clock rates, I honestly don't know what the current thinking is. 160 MHz was definitely a conservative choice (probably too conservative!) motivated by the convenient fact that it was twice the common P1 clock frequency. But I think a higher frequency might be better for many applications. Do we have a sense now of a "safe" upper bound? At one point the chip was spec'd to 180 MHz, but I think we're up to 252 MHz now?
Again, all this is just thinking about conventions or defaults. I'm definitely not trying to suggest that all applications must all use the same clock speed or baud rate! For programs where neither of these really matter, though, what should we pick?