Is the TutorVision rarer than the Keyboard Component?

[intvnut]

I think that the Intellivision memory map has 2k memory reserved for GRAM, but the built in GRAM is mapped 4 times into the memory map so that a request for GRAM card 1 displays GRAM card 1, but a request for GRAM card 65 or 129 or 193 also displays GRAM card 1.

 

This was actually a good thing for memory starved Intellivision programmers back in the day -- it meant that the top two bits of the GRAM address in a Color Stack BACKTAB word were ignored, and the programmer could use these bits to store whatever information they wanted.

 

But it means that to add GRAM the Intelliivision would have to be modified so that Internal GRAM only responds to the 0-63 part of the GRAM memory map (and this would have to be something that could be disabled or enabled for compatibility with existing games...)

 

What's interesting is that you only need that compatibility mode for Color Stack mode, like you said. In FG/BG mode, the GROM gets switched into a mode that forces it to only expose the first 64 GRAM and GROM tiles, because the other bits are used for color information. That mode also ends up affecting the MOBs too.

 

When I did my GRAM expansion hacks a few years ago, I actually did include a read/write sensitive register to turn them on and off. When they were on, the display did look weird in some games, due to flags and such being packed in those two extra bits. Even Space Patrol looked wonky, as I believe I packed scoring information (how much each bad guy was worth) into those two bits.

 

If you build an appropriate state machine outside the STIC, you can also double the vertical resolution by keeping track of whether you're on an even or odd scan line, and using that as an extra address bit. MOBs would behave oddly, though, unless you take into account the MOB fetches. I did do a double-res hack, though, and it looked pretty good.

 

All of these mods require hacking into the private STIC / GROM / GRAM bus, though. :-P

[First Spear]

"Hacking" meaning soldering something within the console itself, right?

 

(snip)

All of these mods require hacking into the private STIC / GROM / GRAM bus, though. :-P

[intvnut]

"Hacking" meaning soldering something within the console itself, right?

 

 

Yes, and possibly cutting circuit traces or desoldering pins and bending them out.

 

Here's some pics from the 128-card modification I made to an Inty 2 (using the RAM that was already in the unit, but partially disabled): http://spatula-city.org/~im14u2c/images/inty2_mod/

 

That one entailed cutting one circuit trace (one address pin was grounded), and then patching an unused address output from the GROM over to both of the AM9114 GRAMs.

 

 

 

And here's an INTVPROG post I had made eons ago showing the double-res hack. It was significantly more complex, because it added the compatibility-mode register I had mentioned previously, and had a small state machine.

 

_________________

 

After last weekend's hack, Carl Mueller asked me if I could use this add'l RAM space to produce a double-resolution display, rather than adding more GRAM cards. That is, could I make 64 8x16 GRAM cards instead of 128 8x8 GRAM cards...

 

I replied "Well, of course! All it needs is a simple counting circuit..." I sketched something up, and then realized with a few more gates I could make it backward compatible with existing games too, by requiring writes to special locations to turn the new feature on and off.

 

So, here's an initial mostly-working version of the hack. For some reason, the odd/even line toggle is wrong for the last three cards of the line. This can be fixed, but it's still annoying. Anyway, I think this proof of concept adequately proves the concept. Also, the mod is a bit more involved than it needs to be. I did the design and then mapped it onto what I had on hand. It wasn't an exact 1:1 match. :-) All of this could likely fit in a single PAL16R8, or at worst a GAL22V10.

 

First: Inty 2 w/ new features disabled

 

http://spatula-city.org/~im14u2c/images/inty_single_res_display.jpg

http://spatula-city.org/~im14u2c/images/inty_double_res_display.jpg

 

(you can see how the right three columns are a bit off, with the odd/even sense inverted.)

 

 

And here's what the actual mod looks like:

 

http://spatula-city.org/~im14u2c/images/inty_double_res_mod.jpg

 

 

I'll see if I can fix that "last 3 cards" issue today (should be doable), and once it's finalized I can post more details of the hack.

 

--Joe

[mr_me]

Fascinating. I had to read up on state machines. The double res feature should be added to jzintv; then we can see some full resolution intellivision graphics. This should have been in the original intellivision.

[+DZ-Jay]

Fascinating. I had to read up on state machines. The double res feature should be added to jzintv; then we can see some full resolution intellivision graphics. This should have been in the original intellivision.

 

State machines are cool and very useful for many applications, not only the domain of hardware control; basically any system that requires controlled transitions from one state to another, such as enemy AI, text parsing, form validation, request/response challenges, game engines, etc., etc.

 

Most programmers tend to employ these in complex solutions even when they are not aware of it. However, being aware of the need for a state machine and consciously employing one gives you greater flexibility (as well as accuracy and stability), since you can change your model from a series of "If this occurs, do that" (which tend to include lots of cases and exceptions); to something more like "if we're in this state and this condition occurs, the only valid outcome is this one."

 

Of course, that's only one flavour: deterministic finite state machines, in which a system can be in only a single state at a time. Non-deterministic finite state machines, in which a system can be in multiple states at a time, are the mind-expanding artefacts that hold the multi-universe together.

 

I love state machines, even if they may end up being the agent of humanity's downfall.

 

-dZ.

Edited August 25, 2016 by DZ-Jay

[intvnut]

The double res feature should be added to jzintv; then we can see some full resolution intellivision graphics. This should have been in the original intellivision.

 

You'd have to write special games to take advantage of it. Existing games wouldn't leverage it. You could modify IntyBASIC to support the extra resolution, but then the games would be emulator-only until someone productizes a hardware mod and enough people do surgery on their Intellivisions.

 

I'd rather tackle other things first.

[+DZ-Jay]

 

You'd have to write special games to take advantage of it. Existing games wouldn't leverage it. You could modify IntyBASIC to support the extra resolution, but then the games would be emulator-only until someone productizes a hardware mod and enough people do surgery on their Intellivisions.

 

I'd rather tackle other things first.

 

Yeah, this is something I grapple with myself a lot... How much effort, time, and energy am I willing to put into crafting my game development framework... versus actually using it to make fun games? The assumption is that life is too short to do both (which I'm sure it is). Is creating and building the tools more rewarding than using them? Am I just wasting time that will never payoff? So I have to decide which one will provide more enjoyment and fulfillment.

 

I suspect you have the same dilemma maintaining the development tools. A lot of projects may seem like neat distractions, but they end up being time-sucking warpholes.

 

I keep all these in a list I call the "Gort Excursion Itinerary," or "Things To Do When The Earth Stands Still." Sometimes, just dreaming about the possibilities is enough.

 

-dZ.

Edited August 26, 2016 by DZ-Jay

[carlsson]

I suppose there would have to be a way to from software determine if the unit has been upgraded/modded so appropriate code and graphics can be applied. From what I understand, at least some games for the Philips Videopac+ G7400 (which is what would've become Odyssey^3 in the US) have a fallback to simpler graphics if the same game is run on a G7000. Same can be said for a few MSX games that actually display better graphics on a MSX2 computer but still are playable on both. There may be more examples of this, but those were two from top of my mind.

 

There also is the announced SGM module from Opcode Games, which still is not entirely speced in public. I've understood it has been taken with some skepticism, but we'll see how it actually turns out and whether there will be room for any third party support.

[SavannahLion]

How rare is the Tutorvision? Maybe its not as rare as you think.

 

Here is possibly a photo of the Tutorvision mainboard.

INTV-1988-small.jpg

This photo came from here. http://forum.arcadecontrols.com/index.php?topic=144540.0

And more info on that board here. https://console5.com/techwiki/index.php?title=INTV_System_3

It looks just like this photo of a Tutorvision here. http://old-computers.com/MUSEUM/photos.asp?t=1&c=1214&st=2

 

Its marked 1988 INTV but Its missing the combined STIC/ram/sound chip. Note that there is a single exec chip labelled wbexec. Intvnut previously pointed out that wbexec could be worldbook exec. He also suggested that if INTV was to make a revised Intellivision for World Book it would make sense to make a common board for both Tutorvision and the INTV Super Pro system (or whatever it was called at the time). The Tutorvision is known to be backward compatible with Intellivision cartridges.

 

On this page (http://www.intellivisionlives.com/media/newsletters/news030831.html) Intellivision Productions describes their Tutorvision prototype as a modified INTV system. Its probably a prototype, but could it just be a standard INTV system?

 

So could it be possible that some INTV systems manufactured and sold in 1989 and 1990 are actually Tutorvisions?

 

Sorry for the necro bump but....

 

That's my board. I bought it sometime around '94 give or take a couple of years from a catalogue. In my initial research to try and discover what the board is, I never came across any information for the TutorVision.

 

I had a sneaky suspicion there was more to the board than what I found, but was stymied. Without anything else, I just stashed it away again.

[mr_me]

It's too bad its missing the square chip at U9. But that is just repackaged common chips. The two ROM chips could be rare. That grom has a unique character set. Don't know if the exec is any different.

 

Have any Tutorvision ROMs been dumped?

[SavannahLion]

It's too bad its missing the square chip at U9. But that is just repackaged common chips.

 

Unfortunately, there was nothing I could do about U9. The board was sold as a "parts" board by a surplus store sometime between 1990 and 1994.

[mr_me]

If someone wanted to and had the skill, they might be able to make a daughterboard and fit some common chips to that square socket and bring this Tutorvision to life. We still need some Tutorvision software to run on it.

 

Still yours is the only good photo I have seen of this board. It's very rare.

[+Lathe26]

The tricky part is that that -appears- to be the STIC chip with arbitration ability for extra RAM (extra RAM is likely inaccessible by default). If there were ROM dumps of Tutorvision games, that might help decode how the SuperSTIC chip worked (I just made up that term).

 

FYI, I am making a few assumptions here...

[mr_me]

It could be a standard STIC in the Tutorvision. The difference is a standard Intellivision simply has a couple of address lines to GRAM missing. If thats the only change then regular Intellivision games will work in a Tutorvision, some might have a few messed up tiles.

 

Edit: The standard STIC can address up to 2KB of gram as is. That's enough for 256 8x8 tiles, enough to buffer the entire screen.

Edited March 10, 2017 by mr_me