Lpc2000

I see now difference between the LPC2138 and 2148 in I/O speed.  I 
have a piece of code that toggles an I/O pin to write to an external 
FPGA.  The time to set then clear this pin is exactly the same with 
the 2148 as it was with the 2138.

This is a listing of the complied code:				
	// Toggle WE pin
   \   00000048   4004A0E3           MOV         R0,#+0x40000000
   \   0000004C   000083E5           STR         R0,[R3, #+0]
    105              FPGA_WE_IOCLR = FPGA_WE_BIT;
   \   00000050   080083E5           STR         R0,[R3, #+0x8]

There are 2 STR instructions in a row to do the set/reset.  As I 
said, no difference in speed with the 2148.

Also, does anyone know where the 8k block of RAM for USB DMA is 
located in the memory map?  I would like to use this for general 
purpose storage.

Randy Ott

--- In lpc2000@yahoogroups.com, "lpc2100_fan" <lpc2100_fan@y...> 
wrote:
> Hi Gennady,
> 
> that has changed in deed, the ports are no longer connected to the 
VPB
> bus, not even to AHB but to the memory bus, which is even faster 
than
> the AHB connected ports. 
> 
> Bob
> 
> --- In lpc2000@yahoogroups.com, "Gennady Palitsky" <gennadyp@j...> 
wrote:
> > Thanks Bob,
> > 
> > > Hi,
> > >
> > > the LPC2148 (LPC2138 with USB) has fast I/O.  In an assemler 
test
> > > program we were able to switch the ports with a frequency of 
CPU/4,
> > > ergo 15 MHz.
> > >
> > 
> > I believe it's not the actual IO toggle speed, but moving of data
> from from 
> > flash to IO (VPB related?) that took extra cycles on 'before 
2148' 
> > controllers. Loading consecutive data from flash and storing at a
> port took 
> > 10 cycles.
> > Is this changed on the 2148?
> > 
> > Gennady