Re: [ECOS] External I/O access on Adder

[Gary Thomas <gary at mlbassoc dot com>]

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On Sun, 2005-03-06 at 00:50 +0700, Sugeng Widodo wrote:
> On Sat, 05 Mar 2005 04:56:16 -0700, Gary Thomas <gary@mlbassoc.com> wrote:
> > On Sat, 2005-03-05 at 09:38 +0700, Sugeng Widodo wrote:
> > > Hi All,
> > >
> > > I have to access external chips with 13 bits address and 16 bits data.
> > > I programmed OR4 and BR4 to use CS4 with address beetwen 0xFB000000 -
> > > 0xFB007FFF and set the area to NOCACHE area. To do that I edited file
> > > Adder.S and hal_aux.c.
> > 
> > What were your exact changes?
> > 
> > >
> > > Lower half of the area is work fine , except I could not catch the CS4
> > > with my logic analyzer ?? But the next half always make my apps crash
> > > when I access it. Sometimes I could access it for 4 times and
> > > sometimes it's crash when I accessed it on the first time.
> > >
> > > Anybody have any clue on that ?
> > 
> 
> I add this on adder.S
>         lwi     r3,0xFB000801
>         lwi     r5,0xFFFF81F6
>         stw     r5,OR4(r4)
>         stw     r3,BR4(r4)
> 
> and add this on hal_aux.c
> CYGARC_MEMDESC_TABLE CYGBLD_ATTRIB_WEAK = {
>     // Mapping for the Adder 8xx development boards
>     CYGARC_MEMDESC_CACHE(   0xfe000000, 0x00800000 ), // ROM region
>     CYGARC_MEMDESC_NOCACHE( 0xff000000, 0x00100000 ), // MCP registers
>     CYGARC_MEMDESC_NOCACHE( 0xfa000000, 0x00400000 ), // Control/Status+LEDs
>     CYGARC_MEMDESC_NOCACHE( 0xfb000000, 0x00008000 ), // I ADD THIS LINE
>     CYGARC_MEMDESC_CACHE(   CYGMEM_REGION_ram, CYGMEM_REGION_ram_SIZE
> ), // Main memory
> 
>     CYGARC_MEMDESC_TABLE_END
> };
> 
> Is it enough or not ?

It looks right, but probably will not work as the 850 only has 4 TLB
registers to use for the memory mapping and you've specified 5.
Try merging the 0xfa and 0xfb segments like this:
  CYGARC_MEMDESC_NOCACHE( 0xf8000000, 0x08000000 ),

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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