[Coco] Fwd: IP packets on my coco

[Dave Philipsen]

So why are we necessarily limiting our scope to the rtl8019 and 
cs8900a?  Just to throw out another option: has anyone looked at the 
CP2200 from Silicon Labs? 
http://www.silabs.com/Support%20Documents/TechnicalDocs/CP2200.pdf

It seems to be well suited to 8-bit processors with a Motorola bus, 
appears to allow interrupts in both multiplexed and non-multiplexed 
modes, generates CRC for transmitted packets, checks CRC of received 
packets, and costs about 6 bucks in single quantities.

Dave



On 6/9/2016 11:29 AM, 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 EEPROM).
>
>       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 CRC
>       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.
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