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Rev2 Game PCB with RAM option

Intellivision PCB

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#1 5-11under OFFLINE  

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Posted Tue Dec 23, 2014 9:21 AM

Well, it required a lot of repairs, but the 2nd version of my Intellivision PCB is working. This version has much wider pin spacings on the chips (which was one of the goals, for assembly reasons), so the repairs were relatively easy to make.

 

If you recall, the 1st version did not have the large mounting holes at the "top" of the PCB, so if the side holders weren't the wide kind, then the PCB wouldn't fit tightly. This one will fit properly into any open-able Mattel shells and LTO shells.

 

The chip with the resistors on top (in blue) is a RAM chip, which will be offered as an option. I've successfully tested it with USCF Chess.

 

ROM size is 128K x 16, and RAM size is 64K x 16. ROM and RAM can be located pretty much anywhere in the 64K space that isn't being used by the console (or its accessories). The plan is to be able to offer ECS style bankswitching, although I haven't tried that yet.

 

On the (more) technical side, I've added one 8 bit latch to free up some pins on the CPLD (and be able to get a CPLD in PLCC package rather than the harder to deal with VQFP package). The upper connector is for programming the flash ROM chip. The side connector is for programming the CPLD. The bottom connector is for game play.

 

Rev2.png

 



#2 catsfolly OFFLINE  

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Posted Tue Dec 23, 2014 9:50 AM

Sounds cool!



#3 grips03 OFFLINE  

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Posted Tue Dec 23, 2014 10:04 AM

No more split power trace, better mounting, this looks awesome. 



#4 Rev OFFLINE  

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Posted Tue Dec 23, 2014 6:06 PM

This is a prototype Im guessing right? Looks good even though I havent a clue at your technical jargon! Ha

#5 5-11under OFFLINE  

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Posted Tue Dec 23, 2014 7:26 PM

This is a prototype Im guessing right? Looks good even though I havent a clue at your technical jargon! Ha

 

It's a prototype. Real product in a month or so.



#6 Rev OFFLINE  

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Posted Tue Dec 23, 2014 10:45 PM

 
It's a prototype. Real product in a month or so.


Cool. ;-)

#7 Oscar G. OFFLINE  

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Posted Wed Dec 24, 2014 2:57 AM

Great project. Thanks for sharing. I have a question though (I am not a technical person): Will this PCB permit to have more "powerful" games in the future?



#8 5-11under OFFLINE  

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Posted Wed Dec 24, 2014 7:56 AM

Great project. Thanks for sharing. I have a question though (I am not a technical person): Will this PCB permit to have more "powerful" games in the future?

 

More powerful? Not really. It will allow larger games than most of those from back in the day, so games could be more complex. The added RAM (temporary memory) could help a bit, too, in making more complex games. Other than that, though, you're still dealing with the same system, with the same graphics and sound and speed limitations.



#9 Oscar G. OFFLINE  

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Posted Wed Dec 24, 2014 8:48 AM

 

More powerful? Not really. It will allow larger games than most of those from back in the day, so games could be more complex. The added RAM (temporary memory) could help a bit, too, in making more complex games. Other than that, though, you're still dealing with the same system, with the same graphics and sound and speed limitations.

 

Thank you for the answer. It makes total sense.

 

For a moment I thought about an equivalent of the FX chip on the SNES  :)



#10 freewheel OFFLINE  

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Posted Wed Dec 24, 2014 9:14 AM

 

Thank you for the answer. It makes total sense.

 

For a moment I thought about an equivalent of the FX chip on the SNES  :)

 

Ya know..... there WERE external video and audio inputs on the cartridge port. In theory someone could make a 32X type attachment which could overlay better graphics and whatnot on the screen. Hell, CD-quality sound if you wanna go nuts. It would be a huge engineering effort and probably cost (tens of) thousands of dollars for a single unit. Oh - and if memory serves, the pin for video differs between the master component and the INTV II. But it's "possible".


Edited by freeweed, Wed Dec 24, 2014 9:16 AM.


#11 intvnut OFFLINE  

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Posted Wed Dec 24, 2014 11:44 AM

 

Ya know..... there WERE external video and audio inputs on the cartridge port. In theory someone could make a 32X type attachment which could overlay better graphics and whatnot on the screen. Hell, CD-quality sound if you wanna go nuts. It would be a huge engineering effort and probably cost (tens of) thousands of dollars for a single unit. Oh - and if memory serves, the pin for video differs between the master component and the INTV II. But it's "possible".

 

I remember when Triton released a side car expansion for the TI-99/4A that allowed you to run PC-compatible software on your TI Home Computer.  The side car interfaced to the Turbo XT expansion box that looked suspiciously like an entire generic IBM PC/XT clone.

 

They also eventually sold an optional IBM PC/XT keyboard you could use with the unit for enhanced compatibility with PC software.  In fact, you could just plug it into the "Turbo XT expansion box" directly, and not even bother with that goofy sidecar thingy.  ;-)  Congratulations, you now own a generic PC/XT clone.  You can put your TI-99/4A away now.  ;-) ;-) ;-)

 

Any hardware we'd plug in to the cartridge port to bring significant video and audio upgrades that aren't in the spirit of the original system kinda feel like that Triton Turbo XT mentioned above, at least to me.  At some point, you're no longer programming the Intellivision, you're programming this thing next to the Intellivision that's borrowing the Intellivision's controllers and TV hookups.

 

So far, I don't think any of the board designs I've seen for the Intellivision cross that line, thankfully.  :-)

 

5-11under's board looks crammed with modern parts, but it's not unreasonable to imagine a cartridge in the late 80s or ~1990 (around when Super Pro Pool & Billiards was to come out) with a significant amount of ROM and on-board RAM if there was a game that needed it.  They'd probably have integrated it onto purpose-built chips so it fit better, but the tech was there.  (As I recall, the higher end GI ROMs also had control lines to simplify interfacing to JEDEC RAMs, which is how Chess and Triple Challenge were able to add on-board RAM easily.) 



#12 First Spear OFFLINE  

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Posted Wed Dec 24, 2014 12:00 PM

This smells awesome... Just so I understand from a software standpoint, how would write/change code to make use of the additional RAM under "normal" circumstances?

 

 

[snip]

ROM size is 128K x 16, and RAM size is 64K x 16. ROM and RAM can be located pretty much anywhere in the 64K space that isn't being used by the console (or its accessories). The plan is to be able to offer ECS style bankswitching, although I haven't tried that yet.

[snip]



#13 freewheel OFFLINE  

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Posted Wed Dec 24, 2014 2:57 PM

Any hardware we'd plug in to the cartridge port to bring significant video and audio upgrades that aren't in the spirit of the original system kinda feel like that Triton Turbo XT mentioned above, at least to me.  At some point, you're no longer programming the Intellivision, you're programming this thing next to the Intellivision that's borrowing the Intellivision's controllers and TV hookups.

 

So far, I don't think any of the board designs I've seen for the Intellivision cross that line, thankfully.  :-)

 

Absolutely agree. It's why I never owned, and still don't own, any "system changer" type add-ons - because that's really all it is. Hell, some of them use the add-on system's intended controllers, basically turning your original console into a hell of an expensive RF/power Y-adapter.

 

I have thought that a video overlay allowing more (and more colorful) MOBs would be pretty slick - and along the lines of what they conceivably could have done by the mid-late 80s. Add on audio capabilities that aren't simply another PSG and it's the kind of thing we might have seen, save for the Crash.



#14 5-11under OFFLINE  

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Posted Wed Dec 24, 2014 3:40 PM

 

5-11under's board looks crammed with modern parts...

 

The PCB is crammed because I purposely chose the largest surface mount chips I could find (that were still in the price range I was looking for). The 0.5 mm pitch chips are fine if you're getting someone else to do the assembly ;) , but because I do the assembly myself, the wider/larger pitch will be much better to deal with in the inspection/repair stage.



#15 intvnut OFFLINE  

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Posted Wed Dec 24, 2014 3:43 PM

5-11under:  Apologies for the thread jack.  It really is neat seeing you expand your board design.  :)  And, it fits in my shells, I imagine.  :)

 

 

 

Hell, some of them use the add-on system's intended controllers, basically turning your original console into a hell of an expensive RF/power Y-adapter.

 

You mean, like this one?  ;) ;) ;) ;)

 

DSCF2238.jpg

 

 

I have thought that a video overlay allowing more (and more colorful) MOBs would be pretty slick - and along the lines of what they conceivably could have done by the mid-late 80s.

 

Unfortunately, the video circuit in the Intellivision I only allowed pulling to white, which was sufficient for the TMS9927 text overlay from the Keyboard Component.  The video circuit in the Intellivision II (and modified Intellivision Is) doesn't really allow video mixing, just an either/or between STIC or external video.

 

The existing STIC can be hacked for higher vertical resolution and more GRAM pretty easily with circuits outside the STIC.  (Character tiles become 8x16 instead of 8x8.)  With a little more work, you can even squeeze in a 20x24 text mode (so you can be all nice and squished like a VIC-20).  And with just a bit more work (and a bunch of RAM), you could even feed the STIC the right data to support a bitmap mode like the TMS9918A VDP's Graphics II mode, which allows each 8x1 pixel region to have any pattern of 2 colors.

 

But, you can't get more MOBs out of the thing (or more colorful MOBs) no matter how you try.  C'est la vie.

 

 

Add on audio capabilities that aren't simply another PSG and it's the kind of thing we might have seen, save for the Crash.

 

Arguably, we did see that in later systems.  For example, Famicom version of Castlevania III has a specialized chip that adds audio channels and some additional graphics effects.  The NES version lacks that chip, though due to limitations on the NES (no external audio input, for example), and so has reduced audio quality and lacks some visual special effects.

 

The fact that the game is still worthwhile with those removals indicate that they weren't essential to the experience, and so really were just enhancements, not game-changers.


Edited by intvnut, Wed Dec 24, 2014 3:44 PM.


#16 5-11under OFFLINE  

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Posted Wed Dec 24, 2014 3:46 PM

This smells awesome... Just so I understand from a software standpoint, how would write/change code to make use of the additional RAM under "normal" circumstances?

 

Good question. I just made the hardware, not the software. ;)

 

In assembly, I'm guessing you could just allocate a certain block of memory, perhaps by following the 42K method, with RAM from $8040 to $9EFF (anywhere or larger is fine, too).

 

In Intybasic, you need to compile with the -jlp option (see the manual), at least for now... and not use multiplication or division except in powers of 2 (2, 4, 8, 16, etc.). Hopefully nanochess will add another compile option to use RAM but not the jlp multiplication and division accelerators.



#17 5-11under OFFLINE  

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Posted Wed Dec 24, 2014 3:47 PM

5-11under:  Apologies for the thread jack.  It really is neat seeing you expand your board design.  :)  And, it fits in my shells, I imagine.  :)

 

It's all good. Yes, the PCB fits both open-able Mattel shells and LTO shells.



#18 intvnut OFFLINE  

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Posted Wed Dec 24, 2014 4:01 PM

 

Good question. I just made the hardware, not the software. ;)

 

In assembly, I'm guessing you could just allocate a certain block of memory, perhaps by following the 42K method, with RAM from $8040 to $9EFF (anywhere or larger is fine, too).

 

In Intybasic, you need to compile with the -jlp option (see the manual), at least for now... and not use multiplication or division except in powers of 2 (2, 4, 8, 16, etc.). Hopefully nanochess will add another compile option to use RAM but not the jlp multiplication and division accelerators.

 

My understanding is that that's the plan.  nanochess says he's going to offer a --cc3 switch that just enables the RAM w/out enabling the MPY/DIV accelerators.  I'm guessing it's not a huge change, and you might see it on an IntyBASIC 1.0.2 or something.  No idea, though.  I have no inside information here.

 

As far as where to map RAM, it's a little tricky in the Intellivision, owing to write-only GRAM aliases at $7800 - $7FFF, $B800 - $BFFF and $F800 - $FFFF.  If your game needs a lot of RAM, you'll have to bank-switch it in an address range that won't interfere with GRAM.  Otherwise writes to the non-GRAM RAM could end up clobbering graphics in GRAM, which generally isn't what you want, is it?  :)  That's also why JLP RAM starts at $8040, to avoid the write-only/read-sensitive STIC alias at $8000 - $803F.   (There's two more, at $40xx and $C0xx.)



#19 5-11under OFFLINE  

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Posted Wed Jan 28, 2015 9:26 AM

With all the wires needed to get the first prototype working, I thought it wise to get another prototype made (along with about 20 completely different PCBs that should keep me busy for a while):

 

Rev2b.png

 

So far it works great. I've tested it with a couple of standard programs, then I added the RAM chip and tested it with the original version of Super Pixel Bros. that required extra RAM. Currently it's running a continuous ROM/RAM test.

 

It fits into standard open-able Mattel shells as well as LTO shells. In about a month or so I'll have these available for whoever needs them (I have the original version available in the meantime). If no extra RAM is required, then the RAM chip doesn't need to be installed (and it's a few dollars cheaper). I still haven't tested ECS bankswitching... that will wait for another day.

 



#20 Rev OFFLINE  

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Posted Wed Jan 28, 2015 9:27 AM

Yay! ;-)

#21 DZ-Jay OFFLINE  

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Posted Wed Jan 28, 2015 10:03 AM

Looking good!

#22 grips03 OFFLINE  

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Posted Wed Jan 28, 2015 12:37 PM

much nicer



#23 BBWW OFFLINE  

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Posted Thu Jan 29, 2015 1:59 AM

You guys amaze me. It is fun to watch sausage (or Bacon for that matter) being made without William Shatner.



#24 pimpmaul69 OFFLINE  

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Posted Thu Jan 29, 2015 3:36 AM

Looking at your first board and i am familiar with the term "quick and dirty job" but damn.... :lol: your second board came out pretty good. Since soldering is my area of expertise im curious on your second board how it was soldered together. Did they get shipped assembled, soldered by hand, baked in an oven, etc. etc.? I only ask cause its something that interests me and im always wanting to find out any new/ different ways people are doing things that could possibly make my life easier. Although ben heck makes my left eye twitch when i watch him work. Always the wrong tool for the job. And his soldering.....

#25 5-11under OFFLINE  

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Posted Thu Jan 29, 2015 6:35 AM

Looking at your first board and i am familiar with the term "quick and dirty job" but damn.... :lol: your second board came out pretty good. Since soldering is my area of expertise im curious on your second board how it was soldered together. Did they get shipped assembled, soldered by hand, baked in an oven, etc. etc.? I only ask cause its something that interests me and im always wanting to find out any new/ different ways people are doing things that could possibly make my life easier. Although ben heck makes my left eye twitch when i watch him work. Always the wrong tool for the job. And his soldering.....

 

This particular board was hand soldered by me. The pitch of the components isn't too bad, except for the small resistor network near the middle of the board. Production boards get soldered with a solder paste dispenser, followed by manually placing the components, and finally by putting the boards on a hotplate for solder reflow. This is also done by me. I have a microscope that helps out a lot.







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