[Coco] Fwd: IP packets on my coco

[Barry Nelson]

It looks to me like the RTL8019AS also has built in auto CRC generation hardware, and so to me with that and the IRQ support, that would make it the clear choice.

http://www.ethernut.de/pdf/8019asds.pdf
The NIC CRC logic comprises a CRC generator for transmitter and a CRC checker for receiver. This bit controls the activity of the CRC logic. If this bit set, CRC is inhibited by transmitter. Otherwise CRC is appended by transmitter.


Conditions

CRC Logic Activities

 
CRC Bit

Mode

CRC Generator

CRC Checker

0

normal

enabled

enabled

 
1

normal

disabled

enabled

 
0

loopback

enabled

disabled

 
1

  	
loopback

disabled

enabled

Quoted from the book:
Networking and Internetworking with Microcontrollers
page 298

Once all bytes are sent, the CRC is calculated by both the CS8900A-CQ and RTL8019AS and is sent to complete the packet.

> RETRO Innovations go4retro at go4retro.com 
> Wed Jun 8 12:38:23 EDT 2016
> 
> 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?
>   * cons
>       o No IRQ capability.  You must poll for all packets
>       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?
> 
> I know the 65XX crowd laments the lack of cs8900a IRQ, but the design is 
> proven.  So, I leave it up to the community.
> 
> 
> Jim