[Coco] CocoNIC

[Brett Gordon]

contiki's uIP stack (in C) would be a wee hard to fit into an 16K rom.  I'm
pretty sure our old BASIC and Nitros need tons of (design) work done to
make use of the NIC.  Standalone apps are in better shape to use the stack
than our current OS'es, barring Fuzix, of course.

I do agree, though, that a pxe boot would be neat- and should be just about
doable in 8k if the tcpip stack was in assembler.

brett
On Sep 15, 2016 2:44 PM, "RETRO Innovations" <go4retro at go4retro.com> wrote:

> On 9/15/2016 10:23 AM, John W. Linville wrote:
>
>> On Thu, Sep 01, 2016 at 07:10:46PM -0500, RETRO Innovations wrote:
>>
>>> Brett sent me some test code, and test 1 succeeded!
>>>
>>> I can talk to the cs8900a  (got the mfr and product ID bytes back)
>>>
>>> Next step is LED blinking, and then on to UDP!
>>>
>> Speaking of which...is there any design/developer info for the card
>> that go along with CoCoNIC? Memory map, schematics, etc? Please send
>> me whatever you have.
>>
>> Thanks,
>>
>> John
>>
>
> The IC is a cs8900a, and the datasheet is here:
>
>
> https://www.cirrus.com/en/pubs/proDatasheet/CS8900A_F6.pdf
>
>
> Section 4.10, on page 75 is the place to start. You will access the IC via
> the I/O space, which allows "indirect" access to the address space via the
> 16 registers.
>
> Specifically, the registers are mapped into the IO space at $ff4x.
>
> That is the complete design.  It has no other functionality at present.
> Which, is an issue of itself, because the CPLD on the unit is woefully
> underutilized.  Thus, if you have additional thoughts around capability,
> I'd love to hear about it (I can get rid of the CPLD, but it helps with
> meeting timing requirements, and PCB routing, so it has some value
> already).  I can easily add a flash ROM, or RAM, or both, but...
>
> <cue soothing music and flashback fade>
>
> I had a lot of PCB space on the 64 version of this card when it was
> finally laid out, and so I decided to put an EPROM socket footprint on the
> board (it was not possible to make the board smaller and have buttons out
> the back, and you pay for PCB size, regardless of what is etched).  Then, I
> added a rotary switch on the back of the board to select banks. The idea
> was that someone would create a "boot" app that would autorun and load a
> custom kerrnal into the machine on boot, like NetBoot PCs.  I produced and
> started selling.  No one created such an app, but people continued to buy
> the optional socket and switch.  Other chastised me for not having a ROM to
> go in there.
>
> <fade to present>
>
> Now, 7 years later, no real ROM is present, and people *still* buy the
> optional rotary switch even though there is no way to use it without the
> ROM, and there is basically no ROM.
>
> So, I am leery of putting a footprint and a ROM on board if there is no
> code to put in it.
>
> But, happy to do so if warranted.
>
> If Darren wanted to work with me to make a EtherFDC, that would work as
> well.   Currently, though, I am not knowledgeable enough on the FDC
> internals to go at it alone.
>
> JIm
>
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