Tutorvision Games on Real Hardware

[mr_me]

Jzintv will automatically emulate a tutorvision when it has a tutorvision exec. The tutorvision grom is optional. The nanochess utility might dump the exec from an actual tutorvision to an ltoflash. I don't think the tutorvision exec has been posted for download but you can make one from the rom files you have. Extract the first 8kB of lathe26's rom file and append it to a mattel exec rom file. Alternatively you can get lathe26's rom file running correctly by turning on extra gram with the -G2 switch.

Edited February 12, 2019 by mr_me

[Swami]

So I tried just adding -G2 to the command line. This seemed to cause an incompatibility where the emulator window wouldn't even open. I found this in another thread:

 

"-g is for specifying the path to grom.bin

 

Decle's hack to add more GRAM to a standard Intellivision is controlled by -G. (e.g. -G2).

that works thank you. i just now got it working with --gramsize=2 as well."

 

Is all I have to do is add "-G2" to the command line or do I need to add another path to the grom? I may also try the "gramsize" command. Could be I replaced something in the latest jzintv bin folder with an older version when I added the GUI and supporting files (Arnauld Chevallier).

 

On a related topic, I wonder how difficult it would be to make an expansion hardware item that adds the extra gram to standard intellivisions.

[mr_me]

Jzintv switches are case sensitive so -g and -G are two different options. The -g switch requires a path to a grom file. The -G switch needs a single digit for the gram size: -G2, -G1, or -G0.

 

It's not possible to add gram through external hardware. The graphics bus does not extend to the cartridge port.

[Swami]

It's not possible to add gram through external hardware. The graphics bus does not extend to the cartridge port.

Right. However, I am wondering if it can be added as a add-on board, like the U1MB RAM upgrade for the atari 8-bit computers.

[mr_me]

I only see nine address lines so I don't think more than 512B is possible using sram. It might be possible if you made a custom chip that was compatible with the intellivision multiplexed data/address bus.

 

Having said that, I kind of remember intvnut connecting the full 1kB of gram in an intellivision ii. Maybe it has ten address lines.

Edited February 12, 2019 by mr_me

[mr_me]

According to this post by intvnut, replacing the gram with 2kB sram is trivial. I guess there are eleven address lines coming out of the grom.

http://atariage.com/forums/topic/235892-super-pro-stic/

[Swami]

According to this post by intvnut, replacing the gram with 2kB sram is trivial. I guess there are eleven address lines coming out of the grom.

http://atariage.com/forums/topic/235892-super-pro-stic/

I wonder if increasing the GRAM would be sufficient to see the Tutorvision games correctly with the 1/2 WBEXEC added to the game files, or if the subsequent 4 bullet points would also need completion to have the higher resolution graphics/font of the tutorvision. Whatever the case, I would think it much, much easier than a CPLD chip with a memory management unit, as used on the U1MB, unless you need to program the circuitry into a CPLD to keep things compatible. It's pretty much beyond me if all five bullet points need completing.

[mr_me]

The narrow font is standard intellivision background resolution and is handled by software. The test that Lathe26 did shows that it will run on a standard intellivision. Expand gram to 2kB and it should look like it does in jzintv with the -G2 switch. Now if there are other cartridges that use the expanded system ram, they would have a problem. Not sure how many people would want to do this however.

 

Edit: If you're referring to the bullit points in that other thread, they have nothing to do with tutorvision, except for the first point.

Edited February 13, 2019 by mr_me

[Swami]

Edit: If you're referring to the bullit points in that other thread, they have nothing to do with tutorvision, except for the first point.

Yeah. These five. Sounds like only the first point is necessary then, which should be trivial.

 

Increasing the number of GRAM slots from 64 to 256. This is trivial, and just requires connecting a large enough capacity RAM in place of the 256 x 8 RAM that's connected to the GROM.

Doubling the vertical resolution of the display. This is a little trickier, as it requires building a small logic state machine and doubling the GRAM storage again, but I have actually prototyped such a hack.

Changing the 20x12 BACKTAB to, say 20x24. This would require replacing the RA-3-9600 System RAM, feeding different data to the STIC in response to the SR1/SR2/SR3 pulses. This is a bit more complicated, but still possible.

Providing a larger BACKTAB area than visible, with a way of changing what portion of it was currently visible, to help with hardware scrolling: Requires similar work to the previous bullet.

A bitmap or pseudo-bitmap mode: If you have 256 GRAM slots, you have a 2-color bitmap mode already. To get a more colorful bitmap mode (such as the VDP's Graphics II mode), you need to replace the RA-3-9600 with something that can provide add'l color data for the BACKTAB to the STIC. (Doable in a similar manner to

[Swami]

Jzintv switches are case sensitive so -g and -G are two different options. The -g switch requires a path to a grom file. The -G switch needs a single digit for the gram size: -G2, -G1, or -G0.

 

It's not possible to add gram through external hardware. The graphics bus does not extend to the cartridge port.

 

Okay. Ended up I must have copied an old driver from the old jzintv version to the new one while copying over the jzintvGUI. I redownloaded the newest jzintv and copied the bin folder contents over to the previous jzintv installation (which was same version) and now the graphics are correct for the tutorvision games.

[Swami]

Now if there are other cartridges that use the expanded system ram, they would have a problem. Not sure how many people would want to do this however.

 

That is a good question. I wish we had access to the other games so we could see if added RAM for the GRAM is sufficient or not for all of them.

 

On my Super Video Arcade, the two small SRAM chips connected to the GROM are socketed, so increasing RAM 4-fold should be very trivial if I knew of the chip of the correct memory and dimensions. would I be looking for a "dip-22" "1024 x 8" "static ram" IC?

[mr_me]

The grom might output 11 address bits but the board might not have lines for them all. If the grom is socketed a small daughterboard can be created that takes both the grom and 2kB gram. The modification can be easily reversible and a switch can be added to cut two address lines for backward compatibility.

[Swami]

The grom might output 11 address bits but the board might not have lines for them all. If the grom is socketed a small daughterboard can be created that takes both the grom and 2kB gram. The modification can be easily reversible and a switch can be added to cut two address lines for backward compatibility.

Something I just noticed is that some logic boards, that look more or less the same (inty1, sears, intv3), have 18 pin GRAM ICs while others have 22 pin GRAM ICs.

[mr_me]

Those 18 pin chips are 1k x 4-bit sram. Mattel must have gotten a good deal on them. Two of them make 1kB so they are obviously only partially wired up. The original design used the 22 pin 256 x 8-bit chips.