Re: [Fx2lib-devel] bulkloop example crashing FX2?

[Dennis M. <de...@ub...>]

Aric Marheine wrote:
> The problem comes down to the fact that the FX2 only has 8KByte RAM, and 
> the FX2LP(which you have) has 16KByte RAM.  So I've got it working as 
> long as I tweek the settings in the Makefile and keep things small.
>
> A bit of a noob question: How can I make use of the external RAM to 
> overcome this shortage?  I'm kind of at a loss as to the command line 
> options to use with SDCC in order to describe my hardware.  My board 
> currently has 0x0000-0x1FFF mapped to internal RAM and 0x2000-0xFFFF 
> mapped to external RAM.
> If I have:
> CC = sdcc -mmcs51 --code-size 0x1800 --xram-loc 0x2000 \
>      -Wl"-b DSCR_AREA = 0x1800" \
>      -Wl"-b INT2JT = 0x1A00"
>
> Then everything works fine, but that gives me little space for code.  
> How do I change this to put my code/data into the external RAM and 
> execute it from there?
>   
I try to create a firmware small enough to fit in the ram on the chip.
The development board has the nice 0x2000-0xffff area memory that you 
can stick a lot of stuff in, but you can then never run your firmware on 
the same chip on a real PCB. (Because it likely won't have the same 
external memory.)  Your approach so far is exactly the way I do it: 
--xram-loc --xram-size, --code-size etc.

Back to your question though, you might try the --codeseg option or the 
codeseg #pragma and then use the linker to place that segment at a 
certain memory location (same as you do with INT2JT).

Glad you found the issue.

-Dennis