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(E)TFE vs. RR-Net
https://www.retrohackers.org/viewtopic.php?f=5&t=209		 Page 1 of 1
Author:  RaveGuru [ Sat Dec 09, 2006 4:24 pm ]
Post subject:  (E)TFE vs. RR-Net
What exactly is the difference between those two? They use the same CS8900a chip and as I understand it, the only difference is the register locations..?
Author:  MagerValp [ Mon Dec 11, 2006 9:22 am ]
Post subject: 
Yep.
Author:  RaveGuru [ Mon Dec 11, 2006 2:12 pm ]
Post subject: 
Thanks. I got the details now. To bone it out a little:

The only difference between TFE/64Net and RR-net AFAIK is the fact that the upper/lower half of the registers are swapped on RR-net because of the RR registers at $de00/01. Hence, it's only a matter of changing a few bytes to make your programs work. Note how TFE/64Net has the "correct" register mapping according to the CS8900A specs, while RR-net's registers are swapped:

Code:
RR-net:

   rxtxreg      = $de08
   txcmd        = $de0c
   txlen        = $de0e
   packetpp     = $de02
   ppdata       = $de04


TFE/64Net:

   rxtxreg      = $de00
   txcmd        = $de04
   txlen        = $de06
   packetpp     = $de0a
   ppdata       = $de0c


In other words the difference for RR-net registers low byte could be expressed as something like rr-net_reg = (original_reg+8) AND 15. I'm sure it's possible to figure out some fast and clever code to write a "combined" driver by using indirect instructions and pointers. But essentially, all you need is the above register definitions to be able to compile your programs for RR-net or TFE/64Net.

Also, care has to be taken to the fact that since TFE/64Net registers begin at $de00 where RR registers are located, all RR related code should be omitted when running/compiling under TFE/64Net.
Author:  Schema [ Mon Dec 11, 2006 4:42 pm ]
Post subject: 
I've been in contact with the developers of the (E)TFE (through a translator though, as the developers only speak Hungarian :wink:) They plan to include a jumper to make the ETFE V2 RR-Net compatible.
Author:  RaveGuru [ Mon Dec 11, 2006 11:37 pm ]
Post subject: 
That's nice. But ETFE is also a daughter board design, right? AFAIK from the pictures on the homepage :)
Author:  Schema [ Tue Dec 12, 2006 3:30 pm ]
Post subject: 
It's a pretty slick approach, actually, though the mechanical design is a bit clunky.

Basically, there's the ETFE board, and three optional adaptors that go between that board and either 1) The IDE64 Shortbus, 2) A clock port, or 3) Directly to the C64 cartridge port (or an expander slot).

So it covers all the possible situations, I think.
Author:  RaveGuru [ Tue Dec 12, 2006 9:10 pm ]
Post subject: 
Sounds nice (although it looks a bit ugly but we Retrohackers aren't exactly spoiled with good looking design, so who cares :D )

Are the ETFE and adaptors available already, and is there anyone who understands english? :P
Author:  Schema [ Tue Dec 12, 2006 9:23 pm ]
Post subject: 
Here, let me quote the emails I received, rather than repeat them. Kajtar is aka Soci of the IDE64 project.

Quote:
---------- Forwarded message ----------
From: Kajtár Zsolt
Date: Nov 3, 2006 8:11 PM
Subject: Re: ETFE?
To: Leif Bloomquist

> Is the ETFE a real product? Is it possible to buy one?

It is real, I've got two ;) There was a production run of 20 units last
time sold out entirely in Hungary.

> How is it different from the RR-Net?

Now the one I've got cannot be buyd anymore. But that's better so, because the new version has a jumper for selecting ETFE/RR-Net compatible operation. (actually the only difference of ETFE to RR-Net was the way how the registers were layed out) Also it has a ShortBus adapter, and it can be used for EPCLink, which is a way faster than anything else so far ;)

The contact address of Fuvesi is commodore(x)freemail.hu, but he has
problems with English, and needed help for translating his pages. I'll ask
him when he plans the next batch. In the near future he will produce
finally the long awaited (at least for me ;) ) IDE splitter. (for
connecting 4 devices to IDE64)


Quote:
He estimates the price of the ethernet card part somewhere between 26-35
EUR. The C64 or ShortBus adapter will be probably more than 13 EUR.

>> -Does it fit in a regular C64 cartridge case?

He also does not know if it fits.

>> -It looks like there are adaptors for IDE64 Shortbus or direct to the
>> C64. Any others? How does this work?

The 16 bit Amiga connection is canned now, it will be 8 bit only, but
still he needs to find where to buy the right type of connector as a new
part.

He hopes that there will be something in the next 6 months, as he already
invested into some parts, but first the boards have to be redesigned.
Author:  Schema [ Tue Dec 12, 2006 9:26 pm ]
Post subject: 
RaveGuru wrote:
Sounds nice (although it looks a bit ugly but we Retrohackers aren't exactly spoiled with good looking design, so who cares :D )


True, but I like my setup to look nice. A case would also help to protect the board.
Author:  Schema [ Tue Dec 12, 2006 9:40 pm ]
Post subject: 
RaveGuru wrote:
The only difference between TFE/64Net and RR-net AFAIK is the fact that the upper/lower half of the registers are swapped on RR-net because of the RR registers at $de00/01. Hence, it's only a matter of changing a few bytes to make your programs work.


I have no electronics skill whatsoever...but...all you would need to do this in hardware would be an inverter on A3, right?
Author:  RaveGuru [ Wed Dec 13, 2006 11:45 am ]
Post subject: 
I don't have any electronics skills either, but it sounds right to me.
Author:  eightbits [ Tue May 08, 2007 2:55 pm ]
Post subject: 
That's pretty interesting. Has anyone tested this?

The inverter on A3 will correctly map the register locations. The only issue I see is the propagation delay of the inverter possibly causing erroneous data on A3. However, with the 74139 ICs in place controlling I/O timing, as long as the inverter is the same speed or faster, it should be OK.
Author:  RaveGuru [ Wed May 09, 2007 8:28 pm ]
Post subject: 
I think it would be a nice feature offering TFE compatibility but I don't want to pay many cents for it :)
Author:  eightbits [ Wed May 09, 2007 9:19 pm ]
Post subject: 
That's a good idea. I'll see if I can do it cheaply. Off the top of my head, I'm thinking that if a single 7404 inverter is all that's needed to remap the register locations, then it's absolutely the easiest thing in the world. A DPDT switch coupled with the inverter should do the trick.
Author:  zap [ Sat May 12, 2007 2:02 pm ]
Post subject:  TFE/64Net and RR-net
ill get one as long as its TFE/64Net or RR-net compatible...

it would be nice to fit it in a cart..


paypal would be nice
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