Lpc2000

--- In lpc2000@yahoogroups.com, "Randy Ott" <k5hj@q...> wrote:
> 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.

Just guessing, I haven't seen a User Manual for LPC214x.  Since the 
GPIOs are now accessible through the fast memory bus, they may well 
be somewhere else in the memory map than the normal VPB peripherals.  
And the speeds you are seeing could be because there exists a set 
of "compatibility" GPIO registers at their old VPB addresses, with 
their old VPB speeds.
An LPC214x User Manual, philips_apps?

Karl Olsen