[Coco] Fwd: IP packets on my coco

John W. Linville linville at tuxdriver.com
Thu Jun 9 13:36:15 EDT 2016


From page 77:

4.10.9  Basic I/O Mode Receive

I/O Mode receive operations occur in the following order (In this
example, interrupts are enabled to signal the presence of a valid
receive frame):

1)  A frame is received by the CS8900A, triggering an enabled


That looks fairly clear to me.  Is the datasheet wrong?


On Thu, 2016-06-09 at 12:29 -0400, RETRO Innovations wrote:
>    IRQs are allowed, but only in memory mapped mode, which require 4k
> of
>    mapping.  Given the requirements of memory mode, most folks map
> the
>    cs8900a in IO mode, which means IRQs are not supported (nor is
>      On June 9, 2016 at 11:19 AM "John W. Linville"
>      <linville at tuxdriver.com> wrote:
>      On Wed, Jun 08, 2016 at 11:38:23AM -0500, RETRO Innovations
> wrote:
>      On 6/7/2016 4:16 PM, John W. Linville wrote:
>      On Tue, Jun 07, 2016 at 12:40:29AM -0500, RETRO Innovations
> wrote:
>      On 6/7/2016 12:31 AM, Stephen H. Fischer wrote:
>      What the ????
>      I see the board image but it quickly is replaced with (Soft
> Porn?)
>      Hmmm, not sure what is going on there... It didn't do that for
> me,
>      butpostimage looks to be putting ads on the side...
>      Anyway, here is another version, off my web site, no ads:
>      http://go4retro.com/downloads/CocoNIC.png
>      Ah...well, that is very tempting. What do I have to do to get
> one??
>      John
>      No big deal to get one prototyped. The main question is:
>      rtl8019 or cs8900a
>      * cs8900a pros
>      o a bit more code available from the 65XX crowd
>      o Slightly easier to produce, as I have all parts here.
>      o AutoCRC?
>      The datasheet I find on the web makes it very clear that the
> chip
>      can generate CRC on transmit.
>      * cons
>      o No IRQ capability. You must poll for all packets
>      Why is this? The datasheet clearly shows IRQ lines -- not
> surprising
>      since the part was designed for the ISA bus.
>      o More expensive to produce (cs8900a is ~$10/pc)
>      * rtl8019 pros
>      o IRQ capability
>      o A bit cheaper to produce ($rtl8019 is ~$5.00/pc)
>      * cons
>      o A bit less code from the 6XXX crowd
>      o A bit tougher to produce, as I need to source the parts (not a
>      huge deal)
>      o No AutoCRC?
>      Bit 0 of the Transmit Configuration Register would seem to offer
>      generation on transmit.
>      I know the 65XX crowd laments the lack of cs8900a IRQ, but the
>      design is
>      proven. So, I leave it up to the community.
>      I have no idea what design issue might have painted them into
> this
>      corner, but the datasheet suggests that this shouldn't be a
> general
>      issue with the chip.
>      John
>      --
>      John W. Linville Someday the world will need a hero, and you
>      linville at tuxdriver.com might be all we have. Be ready.
>      --
>      Coco mailing list
>      Coco at maltedmedia.com
>      https://pairlist5.pair.net/mailman/listinfo/coco
John W. Linville		Someday the world will need a hero, and you
linville at tuxdriver.com			might be all we have.  Be ready.

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