Re: Ethernet

From: André Fachat (
Date: 2000-07-20 19:05:09

> Anyone following comp.sys.cbm will have seen a recent thread on
> Commodore
> networking. Some jumped up little American sysadmin has started making a
> lot of noise about the idea of Ethernet on a CBM machine, as well as
> being

I had a similar discussion before and I looked into the standard
NE2000 networking chipsets.
The problem is that the data rate of the ethernet is too large
to let the 6502 handle it itself. secondly, the DMA mode requires,
as far as I remember, a certain clock rate that does not fit
the C64, so you will not be able to directly glue a simple NE2000
chip to the C64.

The only possibilty I saw was to have a 64k RAM buffer that the 
NE1000/2000 chipset accesses via 8-bit DMA, and the C64 would again
access this buffer via DMA.
Additional issues then are how to bypass the buffer to access the
ethernet chipset's control registers, syncchronizing the different
(asynchronous) clock rates of C64 and Ethernet etc.

The hardware effort, so I judged, was much too high (at least if
you don't have a layout program and a way to etch PCBs...)


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