[Coco] Fwd: IP packets on my coco

[Dave Philipsen]

Not only will it generate CRC on transmit but the datasheet indicates that it also checks CRC of received frames (page 17 par. 3.1.3).

Dave Philipsen

> On Jun 9, 2016, at 10:19 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, but
>>>> postimage 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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