[Coco] WiFi modem.

[Gene Heskett]

On Saturday 20 January 2018 15:58:27 RETRO Innovations wrote:

> On 1/20/2018 2:51 PM, Gene Heskett wrote:
> > But, it enables cards in the cartridge port/mpi that use full
> > address decoding to work at these newly available addresses, this is
> > the precursor dependency.
>
> It does, but the carts are not designed to work at those addresses.
> And, if you are modding the cart to work at such an address, simply
> drive *SLENB low when the cart needs to be accessed.  So, the mod to
> move the address can also fix the issue.
>
> > Imagine what we could do with even one pia fully
> > decoded, that 7 more addresses that are then usable by anything you
> > drop into the mpi. Those unused cs's don't need exported, can't be,
> > not enough pins in the cart interface, but thats 7 or 14 (I think
> > the same drop-in board in the coco could work for either pia by
> > using that chips cs as an input to the board) new addresses usable
> > for each drop-in postage stamp.
>
> Again, the additional PIA cart can simply bring SLENB low when they
> need to be accessed.  Done.
>
All this can be done by the cart? Any timing issues? I ask because 
something in my mpi is causing a huge ground bounce from two signals 
trying to drive the same data lines for around 20 ns in my mpi. Its 
taken heavy braided bonding jumpers connecting all the ground planes 
together and way more gnd/vcc bypassing to make it not a problem. By 
passing in the .1uf mylar cap range. 2 of them.

> I'm not disputing your overall idea, but I do not believe fixing it
> requires anything so substantial.

If slenb can be pulled down fast enough, thats a way around it. Glad to 
hear it.

I'll be pout of pocket for perhaps a few hours, need to hit the grocery 
store, and perhaps I'll get some lathe accessories in the mail box. That 
will take me to the garage after I fix dinner, for an indeterminant time 
as I need to make an arbor to mount a CBN wheel so I can sharpen HSS 
tooling. I found the hard way that it can't be done with diamond because 
diamond is a form of carbon, and it dissolves in the high carbon steels 
used in HSS cutting tools. CBN is cubic boron nitride, and costs about 
20% more than diamond. So we either use alox wheels which abraid quickly 
and lose their shape, or CBN to sharpen HSS tooling.

> Jim


Cheers, Gene Heskett
The above content, added by Maurice E. Heskett, is Copyright 2018 by 
Maurice E. Heskett.
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