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http://spatula-city.org/~im14u2c/intv/tech/master.html

 

According to the above page, pins 16 and 18 aren't exactly known, but pin 20 should be ground.

 

Edit:

Actually this is what it says about 16 and 18.

"These pins are tied to ground on non-Intellivoice cartridges, and left open on Intellivoice-aware cartridges."

Edited by mr_me

does this mean that the backbit just needs to have some special code for certain games?  I guess it's "good" there were only 4 originally made for it?   but not so good for homebrews that don't catch wind of this and get included in the firmware.

The Intellivoice changed / re-used some of the pins on the Intellivision connector.  These pins are used for the voice chip's serial bus for voice expansion chips.  The Intellivoice has 2 chips, the SP0256 voice chip and the SP0640 expansion chip.  The 2 chips are connected together by the same serial bus present on the Intellivoice connector.  The SP0256 has some built-in phrases that every game can use, such as "Mattel Electronics presents".  The SP0640 expansion chip is for custom phrases for each game by sitting on accepting voice data written to it via the normal 16-bit bus, buffering it, and then pumping it out onto the serial-like bus.

 

Given that the "Mattel Electronics Presents" is heard but the rest of the game's voice audio is not, my guess would be that the BackBit is grounding some of the re-assigned pins which prevents the SP0256 and SP0640 from communicating over the serial bus.

You can play Intellivoice cartridges without an Intellivoice, e.g. World Series MLB, so the cartridge leaving 16 and 18 open shouldn't be an issue.  If you have an Intellivoice, they allow the buffer chip to work, whether it's used or not.  Doesn't seem to be an issue just leaving them open all the time.

14 hours ago, evietron said:

I figured it out. I needed to disconnect pins 16/18/20 on the cart from GND. Is there any adverse affect for not grounding these pins on a non-voice ROM?

Oops, I missed this comment before I posted my long comment.  :dunce:

 

It should be fine to leave pins 16/18/20 open.

4 minutes ago, Lathe26 said:

Oops, I missed this comment before I posted my long comment.  :dunce:

 

It should be fine to leave pins 16/18/20 open.

Thanks for the confirmation. Looking at the schematic for the Intellivision, pins 14..28 are all shorted together. It would appear that the Intellivoice repurposed those 3 pins for what is plugged into it. As a voice activated cartridge will leave those 3 pins open, but not actually do anything with them, there doesn't seem to be any harm to leave them floating.

 

If you look at this document, page 13 states that the Intellivision must be tolerant to those 3 pins being connected to ground, but also implies that they don't have to be. This document is what originally tipped me off that these 3 pins might be the issue with not getting any voice.

  • Like 1
12 minutes ago, evietron said:

Thanks for the confirmation. Looking at the schematic for the Intellivision, pins 14..28 are all shorted together. It would appear that the Intellivoice repurposed those 3 pins for what is plugged into it. As a voice activated cartridge will leave those 3 pins open, but not actually do anything with them, there doesn't seem to be any harm to leave them floating.

 

If you look at this document, page 13 states that the Intellivision must be tolerant to those 3 pins being connected to ground, but also implies that they don't have to be. This document is what originally tipped me off that these 3 pins might be the issue with not getting any voice.

I think you mean that the Intellivoice must be tolerant to having those 3 pins grounded by a non-voice cartridge since the doc is the specification for the Intellivoice itself.  I accidentally type "Intellivision" sometimes when I meant to type "Intellivoice".  Short version is that not connecting these 3 pins to ground in the BackBit and leaving them floating should be fine.

1 hour ago, Lathe26 said:

I think you mean that the Intellivoice must be tolerant to having those 3 pins grounded by a non-voice cartridge since the doc is the specification for the Intellivoice itself.  I accidentally type "Intellivision" sometimes when I meant to type "Intellivoice".  Short version is that not connecting these 3 pins to ground in the BackBit and leaving them floating should be fine.

Yes, indeed!

  • 1 month later...

Awesome, evietron A has been really great in communication with me on the backbit site.  Production has been going on.  She's cranking them out a few a day.  I'm around 40th in line so I'm waiting and will report in as soon as I get mine.  Very exciting to know there are at least 39 other intellivision users out there with a multicart!  Hopefully many more now that those who might have been on the fence about trusting preorders for new hardware will take plunge :)

No notifications for mine. But I also ordered one of the chip tester pros as well so mine is likely to be delayed until everything is ready since I believe the chip testers were also pre-order status at the time I ordered the Intelly BackBit cart.

 

1 hour ago, -^CrossBow^- said:

No notifications for mine. But I also ordered one of the chip tester pros as well so mine is likely to be delayed until everything is ready since I believe the chip testers were also pre-order status at the time I ordered the Intelly BackBit cart.

 

No notifications for me, either. I ordered some with the adapters back in April, and recently added on the new Bally Astrocade adapter. I've been in contact with her via email about the order status. Sounds like it will be a bit longer still.

No it definitely does.  I've been in casual communication with @evietron and she confirmed B-17 bomber and others work with it.  I'm still waiting for mine to arrive to really test it, but I take her at her word if she says it does.  

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