Lpc2000

Bob,

Tks for your reply. I am really convinced with your answer. 

For instance, if I use a Flash Memory 90nsec time access and I am 
running @75MHz LPC2220 do you know how many mips we can get from the 
CPU ? 
How do I calculate the performance with a introducing of wait states ?

Tks in advance, Fabio


--- In lpc2000@yahoogroups.com, "lpc2100_fan" <lpc2100_fan@y...> 
wrote:
> Hi Fabio,
> 
> that depends on a few factors:
> 1. access time of the Flash
> 2. ARM mode or Thumb mode
> 3. Between 8-bit and 16-bit bus almost exactly the factor of 2 in
> performance out of Flash.
> 
> 1. The access time will determine the number of waitstates. As a 
rule
> of thumb ;-) you best performance to power ratio will be at the max
> speed for 0 WS Flash.  Example: a 50ns Flash provide roughly a 20 
MHz
> 0 WS access option.  If you run at 25 MHz and need a wait state you
> will consume more power and be slower. 
> 
> 2. In this case use Thumb mode whenever you can while working from 
the
> Flash, it will run faster because the instruction fetch is the 
bottleneck.
> 
> Proposal:  If you need more performance, I would HIGHLY recommend to
> use the LPC2220 instead of the LPC2210. Not only is the 2220 
specified
> for a max. of 75 MHz, much more important it has 64K SRAM instead of
> 16K.  This enables you to load performance critical parts of your
> code, e.g. interrupt service routines or DSP algorithms into the 
SRAM,
> executing 0WS up to 75 MHz.  In this case you might want to use ARM
> mode because there is no bottleneck for fetching and ARM mode will 
be
> approx. 30% faster than Thumb mode. 
> 
> To summarize this, the LPC2220 is pin compatible to the LPC2210 but
> offers 4x the SRAM and this SRAM can be used for performance 
upgrade.
> 
> Just a wild guess, between 16-bit bus executing from external 50 ns
> Flash in Thumb mode and 75 MHz executing in ARM mode from internal
> SRAM is probably a performance increase by a FACTOR of 4x to 5x!!
> 
> Convinced ;-)
> 
> The tough part, the LPC2210 is much easier to get than the LPC2220,
> which is kind of new but afaik not much higher price. 
> 
> Cheers, Bob
> 
> 
> --- In lpc2000@yahoogroups.com, "fcervone1" <fcervone1@y...> wrote:
> > Hi Folks, 
> > 
> > Do you have any idea on what's the maximum performance for 
LPC2210 @ 
> > 60MHz clock we can reach considering :
> > 
> > 1. Accessing one 8-bit external flash code memory bus? 
> > 2. Accessing 16-bit external flash code memory bus?
> > 
> > Fabio