[En-Nut-Discussion] Recommended compiler?

Austin Schutz tex at off.org
Sat Oct 5 19:56:18 CEST 2002


On Sat, Oct 05, 2002 at 11:54:11AM +0200, Harald Kipp wrote:
> >         Also, I note the 8019AS is connected on all 16 address lines. Is is
> >possible to read/write the sram buffer directly? It _looks_ like it's possible
> >from reading the 8019AS pdf, but it's a little vague. I'd like to be able to
> >inspect the contents of the buffer to know how many packets of a certain type
> >are waiting to be read without having to wait for them to get copied into
> >memory using dma. The 8019AS makes note of an 'IOMS' bit that needs to be
> >set via the optional bootrom. Since it hasn't arrived yet I haven't had
> >a chance to play with it.
> 
> The 8019AS has its own internal 16 bit address decoder.
> So all ATmega address lines are connected and the
> controller occupies address space 0x8300 to 0x831F only.
> 

	Other implementations I've seen only have the first four addresses
lines connected. If you can't access the buffer memory, why connect the
other pins? I'm not trying to be difficult, I'm just trying to understand. 
I've been programming for a bit, but this low level stuff is a little new. :-)

> The Realtek is NE2000 compatible. Refer to the DP8390
> datasheet for a much better explanation of the internal
> ring buffer structure.
> 

	I have a copy of the 'at/lantic Software Developer's Guide' which I
think is the right document. It says there's a "shared memory mode" where
that memory is (appears to be.. haven't actually tried it of course)
accessible. I couldn't find a specific DP8390 guide, the closest seems to be
the DP83905 from NS's website. I'm not sure if that's because the
DP83905 is a specific type of 8390, or because the 83905 is a newer
version which is backwards compatible. It wasn't clear from the guide.

	Does the 8019AS support this mode? I know it's ne2000 compatible, but
there are a few realtek-specific extensions. Also, since I don't have the
specific DP8390 guide, I'm not sure if the original ne2000 supported it.

	Thanks!

	Austin



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