Lpc2000

--- In lpc2000@yahoogroups.com, "Gennady Palitsky" <gennadyp@j...> 
wrote:
> Thanks a lot for the reference.
> Too bad it's not documented anywhere in Philips' papers.

I once asked Philps for a spec and they weasled out of it saying that 
there were too many variables. 
There are a few, including clock speed, MAM settings, VPB speed etc.
The main problem is die to the way Philips attached the core to the 
GPIO. If they'd one it on the "fast bus" instead of the VPB things 
would be a lot faster.

The Atmel SAM7 parts have much faster GPIOs but still not anyhere near 
single cycle.I prefer working with Philips than Atmel, but this one 
point was enough to make me choose an Atmel SAM7 part.

> 
> So it seems that the BEST result I can get with loading consecutive 
data 
> from flash and storing at a port is 10 cycles...
> (what with my 14.318MHz clock is ~230nS, actually a bit more then 3.
7MHz).

That's about right.

> 
> Is there ANY way aroung it? Since I need a byte every oscillator 
cycle (3 
> cpu cycles), the only way I see is to output 4 bytes at a time to 
pld and 
> multiplex it 4 times - every oscillator cycle.
> 
> Any ideas?
> 
The only way to get the data out fast with a Philps LPC21xx device is 
going to be using some sort of mechanism on the external memory bus.