riscy
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Re: Ethernet stuff

To: riscy@pyramid.com
Subject: Re: Ethernet stuff
From: Andreas Busse <andy@resi.waldorf-gmbh.de>
Date: Thu, 8 Jul 93 11:48:38 +0200
Reply-to: riscy@pyramid.com
Sender: riscy-request@pyramid.com
>    Does "oem" mean some sort of reverse engineering or simply to buy them ?

> Original Equipment Manufacturer - ie : do what everyone else did, 
> and clone National Semi 8390 eval boards... 

I see. Finally this *is* reverse engineering, but I don't mind...

>    I like to see ethernet on board. People can leave the sockets empty
>    if want.

> Agreed.  However, how are you going to socket pulse transformers, the 
> DC->DC convertor, etc?  IMHO, this is a good argument for propriety
> slots on the low speed bus! 

Ok, putting transformer in sockets is not a good idea, but I think
the most expensive parts are the controller chips. Am I right ?

> Leaving empty sockets on some boards will reduce the cost for these
> people.  However, sockets still cost money, as does the realestate
> lost to the sockets, so it's an imperfect solution.  
>
> [...]
>
> Having the SCSI, ethernet, serial ports, etc. on daughter cards 
> on the propriety bus would keep everybody happy and solve all these
> problems.

But daughterboards cost money too, probably more than sockets.
And we still need connectors then.

> Also : 
> 
> - Bigger circuits (ie, ethernet) eat space on cheaper 2-layer
>       boards rather than the expensive mainboard.

We have to figure that out.

> - If we use the left rear of the motherboard (adjacent to the ISA
>       slots) for the bus, everything is next to a hole in the 
>       case and our connector mounting problems disappear.

This is a good idea anyway.

> You don't have to refresh DRAM, and for an 8K chip the price difference
> won't be that noticeable.

You mean SRAM, right ?
    
>     Please correct me if I'm wrong: What other supplies do
>     we need than +5, -12 and +12 ? All these come out of
>     a standard PC power supply.

> 15V.

Ok. What current ? If it's not that much, there might be
a cheap solution. I'm gonna ask our analogue guys.

Andy

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