Intellivision as Serial Terminal

[intvnut]

From that link:

"The Intellivision 2 (well, at least the Intellivision 2s I've looked inside) can support up to 128 GRAM tiles, rather than 64, but it requires hardware modification. See, the Intellivision 2 uses 1K RAMs in place of the 256 byte RAMs that were in the original. To force strict compatibility with the original Intellivision, Mattel tied the extra address lines to ground."

 

This is hilarious. I have generally not been a big fan of the Intellivision 2 (liking the original best), and I think I had two pass through my possession in times past. One was left out in the rain and was in bad shape and I might have given that to someone as parts. But all and all, wishing I had a Intellivision 2 to try this out now.

 

Besides, would match my ECS better.

 

All and all, a good find that the ram was already there, but just govened down to be compatible with the older Intellivisions.

 

It gets even better: The Intellivision has 240 bytes of 8-bit scratch RAM. The Intellivision 2 actually uses a pair of 2114s for that also. So, it actually has 1K bytes of scratch RAM, but it's wired up so only 240 bytes are available.

 

Again, for backward compatibility...

 

Actually it was for bi-directional compatibility. Mattel was indeed concerned about releasing titles that worked on the Intellivision 2 but not the Intellivision 1. So, not only did they not want to break titles that worked on Intellivision 1, they also did not want to make a system that could support titles the Intellivision 1 could not support. They were holding off until Intellivision 3 to make that break.

[doctorclu]

 

It gets even better: The Intellivision has 240 bytes of 8-bit scratch RAM. The Intellivision 2 actually uses a pair of 2114s for that also. So, it actually has 1K bytes of scratch RAM, but it's wired up so only 240 bytes are available.

 

Again, for backward compatibility...

 

Actually it was for bi-directional compatibility. Mattel was indeed concerned about releasing titles that worked on the Intellivision 2 but not the Intellivision 1. So, not only did they not want to break titles that worked on Intellivision 1, they also did not want to make a system that could support titles the Intellivision 1 could not support. They were holding off until Intellivision 3 to make that break.

 

Ahhh and I see the Intellivision 3 did not get released. So this upgrade puts us a bit closer ram wise to what that might have been.

 

Anyway, I think I have located a local Intellivision 2 but no power supply with it. Any chance the ECS power supply would work with the Intellivision 2?

[doctorclu]

Looking at the first message from an Intellivision keyboard on Aatarige. Was hell getting here but where thres a whip theres a way.

 

My inspiration for this message from an Intellivision in case no one caught it:

 

https://www.youtube.com/watch?v=YdXQJS3Yv0Y#t=156

Edited April 13, 2014 by doctorclu

[+Lathe26]

How about this version...

 

[doctorclu]

LOL!! Not originally, but it is now.

 

So what's the word, can a ECS power supply work with an Intellivision 2? If not, what is the voltage, amperage, and polarity of a Intellivision 2 power supply?

[+Lathe26]

I don't have the volts/amps numbers in front of me, but I can confirm that the 2 power supplies have very different values. They are not compatible or interchangeable.

[+Lathe26]

I dug out my Intellivision II adapter. Its output is 16.2V at 955mA that is AC current (not the typical output of DC you find at Radio Shack). Various online posts say the Intellivision II is forgiving with other voltages from other power supplies but I've never tried.

[doctorclu]

I dug out my Intellivision II adapter. Its output is 16.2V at 955mA that is AC current (not the typical output of DC you find at Radio Shack). Various online posts say the Intellivision II is forgiving with other voltages from other power supplies but I've never tried.

 

Any idea if the power supply is tip positive or negative?

[intvnut]

 

Any idea if the power supply is tip positive or negative?

 

It's AC. The tip is both positive and negative. :-)

 

Also, this old thread may be useful: http://atariage.com/forums/topic/10392-intellivision-ii-power-supply/

[doctorclu]

From that link:

"According to Deathskull Laboratories, alternative power supplies that supposedly work in the Intellivision II include the Atari 5200, Atari Jaguar, and TurboGrafx-16 power supplies. I also found a message on Usenet that the NES power supply will work, although I don't think the connector will fit. I have seen several messages from people saying the 5200 power supply works fine, and it has a Center Positive polarity."

 

Atari 5200 power supply eh? Ok, THAT I can do easy.

[doctorclu]

Well I have sourced two Intellivision 2s and hopefully I can get one to work. The memory hack is intriguing. However....

 

... it just occurred to me, the instructions on the Yahoo group look pretty start forward and in the end it would let you display 128 tiles, which is great. But then I thought, you know, even if you made a terminal program that could take advantage of this with better font resolution ... Would the Cuttle Cart menu display properly to allow you to even see the terminal program on the list and load it?

 

Does the upgraded ram conflict with the CC3 serial port? Just two thoughts that came to mind as I get ready to do this.

[intvnut]

Well I have sourced two Intellivision 2s and hopefully I can get one to work. The memory hack is intriguing. However....

 

... it just occurred to me, the instructions on the Yahoo group look pretty start forward and in the end it would let you display 128 tiles, which is great. But then I thought, you know, even if you made a terminal program that could take advantage of this with better font resolution ... Would the Cuttle Cart menu display properly to allow you to even see the terminal program on the list and load it?

 

Does the upgraded ram conflict with the CC3 serial port? Just two thoughts that came to mind as I get ready to do this.

 

The GRAM already has reserved addresses in the memory map to handle an upgrade to 256 tiles. There's no need to worry about RAM address conflicts. If you write to those addresses today, they just alias down onto the current 64 GRAM cards.

 

Will the CC3 menu work? Yes, it'll work just fine. Will it display properly? I'm not sure—the graphic elements that show the cuttle fish and "Chad Schell's Cuttle Cart" may or may not display correctly depending on whether he's set bits 6 and 7 in the GRAM card number. (I bet he hasn't, and it'll display fine.) Even if those graphic elements don't display correctly, the portions of the screen that use the built-in GROM font will display unmodified.

 

You can always add a simple DPST or DPDT switch to turn the hack off, disconnecting the address line from the GROM and re-connecting it to ground.

 

The biggest issue is that nothing off the bat will make use of the extra GRAM cards. And if you want to use the extra GRAM for a denser font for the terminal software, 128 cards isn't likely to be enough.

 

You can go to 256 cards (and match what we believe the Tutorvision supports) by adding a 2K x 8 bit RAM (or larger). That will require you to build a small daughtercard. With that, though, you can effectively get a 159x96 2-color bitmap display, as I described previously.

 

If you're willing to work with me to develop some additional logic (and add a 4K x 8 bit RAM or larger), we should be able to develop a double vertical resolution 256 GRAM card modification. Now that would give you a 159x192 2-color bitmap. You could very possibly approach 40x24 text resolution, although 32x24 is more likely to be actually readable. 40x24 would limit you to a 4 pixel wide font, and that really pushes the limits of readability. For example, you can't really distinguish "w" and "m" with only 4 pixels. At 32x24, you have similar problems with a 5px wide font, but you can start to distinguish "m" from "w" in other ways, vertically.

 

No promises on how much time I'll actually have available for any of this...

Edited April 15, 2014 by intvnut

[Games For Your Intellivision]

I think that it would be cool to develop some mods for the original Master Component to allow for more GRAM, and then support the mod in certain new games. It certainly would be fun to see the 'what if?' and new games could take advantage of the enhancement if present and do standard programs if not.

[doctorclu]

I think that it would be cool to develop some mods for the original Master Component to allow for more GRAM, and then support the mod in certain new games. It certainly would be fun to see the 'what if?' and new games could take advantage of the enhancement if present and do standard programs if not.

 

I completely agree. I am all about getting a smaller font and better resolution for a better term program, but I'm sure if we expanded the memory and GRAM the Intellivision could kick out some amazing stuff. The Intellivision is already amazing, but this would be like taking the governors off an engine and seeing how fast the engine could really go.

 

 

The GRAM already has reserved addresses in the memory map to handle an upgrade to 256 tiles. There's no need to worry about RAM address conflicts. If you write to those addresses today, they just alias down onto the current 64 GRAM cards.

 

Will the CC3 menu work? Yes, it'll work just fine. Will it display properly? I'm not sure—the graphic elements that show the cuttle fish and "Chad Schell's Cuttle Cart" may or may not display correctly depending on whether he's set bits 6 and 7 in the GRAM card number. (I bet he hasn't, and it'll display fine.) Even if those graphic elements don't display correctly, the portions of the screen that use the built-in GROM font will display unmodified.

 

You can always add a simple DPST or DPDT switch to turn the hack off, disconnecting the address line from the GROM and re-connecting it to ground.

 

The biggest issue is that nothing off the bat will make use of the extra GRAM cards. And if you want to use the extra GRAM for a denser font for the terminal software, 128 cards isn't likely to be enough.

 

You can go to 256 cards (and match what we believe the Tutorvision supports) by adding a 2K x 8 bit RAM (or larger). That will require you to build a small daughtercard. With that, though, you can effectively get a 159x96 2-color bitmap display, as I described previously.

 

If you're willing to work with me to develop some additional logic (and add a 4K x 8 bit RAM or larger), we should be able to develop a double vertical resolution 256 GRAM card modification. Now that would give you a 159x192 2-color bitmap. You could very possibly approach 40x24 text resolution, although 32x24 is more likely to be actually readable. 40x24 would limit you to a 4 pixel wide font, and that really pushes the limits of readability. For example, you can't really distinguish "w" and "m" with only 4 pixels. At 32x24, you have similar problems with a 5px wide font, but you can start to distinguish "m" from "w" in other ways, vertically.

 

No promises on how much time I'll actually have available for any of this...

 

Well you know I am definitely up for tinkering with anything regarding terminals and the Intellivision at this point. I've ordered two Intellivision 2 consoles to try the modification to boost the ram, and when you are ready to tinker with a terminal program with the extended ram I will be up for trying it.

[doctorclu]

I'm curious, I've just noticed the INTV III console and that is a cool looking system with that Intellivision 1 look.

 

Does the INTV III have the unused ram like the Intellivision 2?

[+intvsteve]

Would have to open it up to check, but I'd expect it does, as those were built even later than the Intellivision II. If intvnut's suppositions are correct (and I bet they are) sourcing those old late 70s era obscure chips was l likely difficult by the mid/late 80s.

[intvnut]

Ok, while googling for pictures of an Intellivision 1 / Intellivision System III style mainboard, I came across this strange bird:

 

http://www.the-liberator.net/site-files/retro-games/hardware/Intellivision-1/intellivision-1-1981-kalex.htm

 

It looks like this board still uses the GTEμ 256-byte RAM chip for scratch RAM, but not for the GRAM. If you look in the upper left hand corner of the main board, you can see two 2114s. These are the GRAMs.

 

 

Digging around some more at the same site, it appears at least some System IIIs use a similar motherboard layout. http://www.the-liberator.net/site-files/retro-games/hardware/Intellivision-III/intellivision-iii.htm

 

But, if you look in the same spot on that mainboard, you'll see a different pair of chips there. These are just a 2nd source version of the GTEμ 256-byte RAM chips.

 

 

 

 

So... it appears they had couple of different, closely related designs, and they shipped whatever they could get the parts for.

[intvnut]

Aha: Here's the thread that had the Intellivision 1 mainboard (actually, a Sears SVA, I believE) with 2114s/9114s in place of the GTE chips, for both the GRAM and the scratch RAM: http://atariage.com/forums/topic/204917-reason-i-started-collecting-intellivision/

[Rev]

I concur.

[intvnut]

BTW, check out this gem from Dave "Papa Intellivision" Chandler's website: http://papaintellivision.com/pdfs/CCF10242011_00007.pdf

[doctorclu]

BTW, check out this gem from Dave "Papa Intellivision" Chandler's website: http://papaintellivision.com/pdfs/CCF10242011_00007.pdfHuh

 

Huh, now this is nice. I haven't looked fan into this, but I did notice this bit on the first page:

 

 

Is that possible with the standard Intellivision console? This didn't have to tap into any features on the Keyboard Component right?

[intvnut]

 

Huh, now this is nice. I haven't looked fan into this, but I did notice this bit on the first page:

 

Screen shot 2014-04-25 at 5.42.48 PM.png

 

Is that possible with the standard Intellivision console? This didn't have to tap into any features on the Keyboard Component right?

 

If you read through this and related documents on the website, they all mention adding some external video capability to the Intellivision, either using the video chip in the Keyboard Component, or including it in the modem add-on.

[Rev]

BTW, check out this gem from Dave "Papa Intellivision" Chandler's website: http://papaintellivision.com/pdfs/CCF10242011_00007.pdf

 

So much cool stuff on that site.

[doctorclu]

Here's one link (dang, harder to find than I thought:

https://groups.yahoo.com/neo/groups/intvprog/conversations/messages/5884

 

 

Well I gave this a try tonight to see if I could make the 128 tiles mod happen. I cut the A9 leads to ground and attached the A9 leads of the GRam chips and connecting them to the 12 pin of the Gram itself.

 

 

My results with the Gram128 test were less than stellar

 

 

When I tested TRON Deadly Discs it was like I was playing the Aquarius version with all the text symbols everywhere.

 

Anyway, if there are any other steps I left out let me know, or if I fried the Intellivision 2, cool nuff... it was bought to tinker with.

[intvnut]

 

Well I gave this a try tonight to see if I could make the 128 tiles mod happen. I cut the A9 leads to ground and attached the A9 leads of the GRam chips and connecting them to the 12 pin of the Gram itself.

 

100_1042.JPG

 

My results with the Gram128 test were less than stellar

 

100_1041.JPG

 

When I tested TRON Deadly Discs it was like I was playing the Aquarius version with all the text symbols everywhere.

 

Anyway, if there are any other steps I left out let me know, or if I fried the Intellivision 2, cool nuff... it was bought to tinker with.

 

If that screen shot is showing what I think it's showing, then the mod works just fine. My memory's hazy, but IIRC, the Gram128 test copies the first 128 cards from GROM to GRAM, and then displays an 8x16 arrangement of tiles from GRAM. With the mod absent, the first four rows will look like the second four rows. Either you'd get two copies of the numbers/uppercase half of the set, or two copies of the lowercase/graphics half of the set.

 

With the mod present, all 128 cards have a unique image.

 

 

Existing games that do not expect the additional 128 GRAM cards, though, will display unexpected things. :-) That's because they may store flags or other things in the bits that the GRAM previously ignored. That explains Deadly Discs. So, to retain compatibility with existing games, you'll want to add an SPDT switch on that line, to switch A9 on the GRAM between the A9 from the GROM, or ground.

 

(My double-res hack tried to add a small state machine to switch the hack on/off in hardware using parts from my junk drawer. It worked, but was most certainly a hack. A manual switch is much easier to get right.)