Lpc2000

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