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#99891 - 05/26/15 02:29 PM The Vidéoway emulation thread  
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plgDavid Offline
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Hello!

Recently got my hands on a Vidéoway terminal (after looking for one on and off for a long time). What the hell is that? Well From the official FAQ:

"Videoway was the first interactive, addressable television entertainment system in North America. Implemented by Videotron in 1989, this system was connected to the subscriber’s television and used as a decoder for scrambled channels, as a gaming and movies on demand rental service, as well as a source of interactive information for banners, the weather, the lottery and the stock exchange."
More: http://support.videotron.com/residential/television/faq-videoway

What is interesting is that this is really an 8bit computer that had unique and official ports of Q*Bert and Burgertime, and a lot of clones: Styx (QIX). For many people in the province of Québec, Canada, this was the first glimpse of not only video gaming, but also of interactive TV.

See the games here:
https://www.youtube.com/watch?v=UTSebgSdFBU (Q*Bert at 11sec)
https://www.youtube.com/watch?v=80CKvFqFyBU

Before you get exited over the prospect of getting to play these games, I need to tell you that they are (we really hope!) stored in a vault at Videotron (one of the biggest ISPs in here).

The analog cable channels that continuously pushed the blocks of data for those games downstream have been replaced with HD signals in or about 2006/2008. So whether or not the company decides to ever provide these later on for their historical importance is anyone's guess.

More here (french)
http://fr.wikipedia.org/wiki/Vidéoway
And google has plenty.

So! As a nerd, I was always curious to know how this thing worked. What kind of CPU it had, etc, and possibly emulate 'something', even if its just a display saying the cable is not connected. Do some home-brew, a song, whatever.

I hope to provide more info on my progress in this thread as I go along. It's a pet project of mine.

[EDIT] Why is it rare? Because technically these boxes were only rented, never sold to the customers. So they had to give the units back to Videotron when they upgraded. Finding a working unit (from a video game collector) was a nearly a miracle.

Last edited by plgDavid; 05/26/15 07:17 PM.
#99892 - 05/26/15 05:19 PM Re: The Vidéoway emulation thread [Re: plgDavid]  
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Shideravan Offline
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Very interesting system and a very interesting piece of gaming/computer history, plgDavid smile


"A user interface is like a joke. If you have to explain it, it's not that good."
#99895 - 05/27/15 01:03 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 1: Does it work?



Starting an emulation project with a dead system is much more frustrating. First steps taken were to plug the actual thing and see if it showed anything.
A sign. "Please wait till I connect to a non existent analog network", erm or something like that.

Well to my surprise, yes! This is what I get when plugin it in:



Short vine of the scanning process

This is the (I assume) build-in bootloader code trying to get a signal from the cable company. It loops through analog channels and tries to find data.. unsuccessfully. You can see the typical mid 80's fonts and resolution at work. My guess was always some form of MSX+ VDC, like a V9938 perhaps?

Anyway, I always wondered if by any chance there were some left over data signals on the analog cable even now. My ISP is in _fact_ Videotron on cable modem, so wouldn't hurt to try right?

But No.
Analog is dead DEAD.

Nice screen though!




Last edited by plgDavid; 05/27/15 02:08 AM.
#99896 - 05/27/15 01:16 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 2: What can we learn just with the writings on the device?

Underneath the device contained parts of the answer:


A patent number (and long expired)
http://www.google.com/patents/US4623920

Lots of info on the broadcasting and decoding of data in there, but little on what really interests me:



We need to know more!

#99897 - 05/27/15 01:27 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 3: OK open the damn thing already!

There was a pink metal rivet protecting the 30 year old IP on there. (a big fat screw driver took care of it).

Lifting the top casing.... huuuhhh thats a LOT of heavy shielding!

All the analog part being completely useless now, I removed most of those boxes:


OK! Now we are getting closer! ... but does it still work? Yes it does, so the VDC/CPU does not need all that top stuff to display a signal and to boot. Great!

My 20$ is on the middle box with the two pink protection rivets.

Last edited by plgDavid; 05/27/15 01:54 AM.
#99898 - 05/27/15 02:08 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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There's rather more stuff in there than I was expecting.

#99912 - 05/27/15 05:18 PM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 4: Getting to the CPU.

They really didn't want people to pry into this. So I carefully took metal scissors and cut my way through the casing:


In an uncommon fashion, the DIP chips are soldered in a surface mount manner (not through hole). PROBABLY so that the leads were not accessible from the underside and/or to add extra shielding, who knows.

Removing the sticker on the 40pin chip on the left unveils an MC68A09EP



Other than that:

1xTMS27PC128-20NL (16KiB mask rom)
1xHY6264LJ-10 ( 8KiB static ram)
8xKM41C464J-8 (64k4bit - totaling 256 KiB of dynamic video memory (assumed)
and one big ass 100 pin QFP custom chip from "LSI LOGIC CANADA",
marked "L4A0412 221E158-01 VIDEOWAY NEG 9050 /\ EX0332 HONG KONG"

This is what I think serves as Video Display controller, bus marshaller, address decoder, I/O interface, you name it.


Last edited by plgDavid; 05/27/15 05:54 PM.
#99915 - 05/28/15 12:06 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 5: Dumping the ROM.

De-soldering surface mounted DIP chips is odd but not that hard. the problem is that I really didn't want to break any ROM pins doing so. Removed both CPU and ROM chips, and cleaned the PCB surface carefully afterwards of old solder and flux.




The CPU is replaceable (I have two 68B09E as spares for Arcade stuff), so I went fast on that.... however I especially pampered the ROM chip. Its bent pins carefully inserted in a dual wipe socket and dumped it:





The ROM had those checksums:
CRC(6E5B2615)
SHA1(ED20BC47067F0B8B0176A3193BFFB26D555841F3)

And contained the text seen in the boot picture.

As I always do in my research, I copy the contents of a fresh ROM dump back onto a known good EPROM, and try to see if it behaves the same if I placed it again in the device. And as expected it did.



I'm now confident the dump is good. And the sockets will allow me to move on to the next steps!
(notes the sockets are in fact two SIP's each, so that I can trace the board later)


Last edited by plgDavid; 05/28/15 12:15 AM.
#99918 - 05/28/15 02:13 AM Re: The Vidéoway emulation thread [Re: plgDavid]  
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ICEknight Offline
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This topic is really interesting. Thank you for showing us the process of dismantling and dumping this thing.

Originally Posted By plgDavid
The analog cable channels that continuously pushed the blocks of data for those games downstream have been replaced with HD signals in or about 2006/2008. So whether or not the company decides to ever provide these later on for their historical importance is anyone's guess.
Do you know if the data used for these games was carried in the same way as the Teletext was in other analogue TV channels?


The data for each page of a channel's Teletext was consecutively included on each frame of the broadcasted image that the receivers got, encoded within the non-visible area. This could have been a very practical way for broadcasting these games' data in succession, with the receiver waiting for the signal of the selected game to begin, then copying the data it gets frame by frame into RAM, then running the game from it.


I'm asking because this Teletext data could actually be saved via good quality VHS recordings. I distinctly remember being able to access a review for the ZX Spectrum version of Bionic Commando while playing a recording of a TV program of that time, many years afterwards (although some TVs were less prone to correctly recognize the signal fully, and sometimes displayed too much garbage along with the readable strings).


So, if the data for these games was handled in a similar way, this would mean that it may be possible to recover some of them or at least part of their data, if somebody still has some good VHS recordings of any programs that were being aired by those channels before they were discontinued.


I hope this can lead to some good news.

#99932 - 05/28/15 02:55 PM Re: The Vidéoway emulation thread [Re: plgDavid]  
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plgDavid Offline
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Part 6: Address space and preliminary emulation.

Since the 6809 interrupt vectors needs to be in the last bytes of the 64KiB address space, it is the first thing you will look at:

SWI3 FFD6
SWI2 FFDB
!FIRQ FFE0
!IRQ FFE3
SWI FFE8
!NMI FFEB
!RESET 4011

4011? that means the ROM is mapped/banked in a few places?

Mirroring the rom in [C000:FFFF] (so that the IRQ vectors are in their right spot) as well as [4000:7FFF] seems to make it boot, but it hangs waiting for bit 6 to be up on $F892 .. this of course means the ROM is not 'seen' in that memory spot (a ROM offset cannot change itself, so this code would not work)...


Last edited by plgDavid; 05/28/15 03:00 PM.
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