JohnPCAE

I've actually built option #4 and I'm trying to make it work, but so far the Pi Pico hangs or something when I plug a USB device into it. The nice thing about it is that it gets its own separate power supply and can be worked on without an Inty present. I wonder how the Keyboard Component would disable the wired hand controllers, since those are connected to the Inty's sound chip.

You could take some of the code from the ACC and build a board using a Raspberry Pi Pico and three SN74LVC245 chips as well.

I guess this begs the question, what do people think is the best way to give the Inty USB connectivity? (1) Make something that plugs directly into the cartridge port (2) Go through the Intellivoice expansion bus (3) Go through the ECS expansion bus (4) Go through the ACC parallel port Option (1) is actually the easiest to do, but it means lengthening the "train" of components that hang off the cartridge port. The Inty could really use something like the C-64's user port, but you need one of the other three plugin modules to get something like one.

I woke up in the middle of the night with an idea. Not all Intellivoice units have the expansion port IDC header, but all Intellivoice II boards would. Also, the Intellivoice II case has an ECS-like expansion door that's properly set up over the expansion port. So, what's stopping me from designing an add-on that gives, say, access to a USB keyboard and mouse? Connecting to USB should theoretically only need a Raspberry Pi Pico and three SN74LVC245 chips. I've even looked into such a design that would connect to the Intellivision bus directly. The question is, how does the Intellivoice expansion bus work? From the service manual it looks like it revolves around the SPB640 chip, but I don't have the datasheet for it. All I have is a die shot of the decapped chip. Does anyone have the datasheet and/or has anyone delved into how the Intellivoice expansion bus works?

So is someone going to tell us what "it" is?

Here are the latest NanoVoice files (version 1.6). This should be the final version. I'm going to hold off on releasing the Intellivoice II files until I get the correct daughterboards in the mail. I want to first make sure that they fit in the case. NanoVoice_1_6.zip

Aha. It turns out that not all LM324N chips are created equal. Transplanting the TI LM324N from the Mattel Intellivoice to my board got rid of the high-pitched whine. The one I was using before was made by National Semiconductor, and yes, it's also marked as LM324N! So I can now pronounce the circuit design as good. The chip is used in an active filter (search for Generalized Impedance Converter for more info) that most likely filters out that whine. I also verified that the PWM data that's being sent to it is the same in both the Mattel board and in mine. Two articles that helped me are linked below. They're part of a larger blog titled The Filter Wizard Remastered that I'll also link. https://www.planetanalog.com/gee-i-see-the-ins-and-outs-of-generalized-impedance-converters/ https://www.planetanalog.com/lowpass-filters-that-dont-a-tale-of-leakage-current/ https://www.planetanalog.com/category/blog/the-filter-wizard-remastered/ The result of all of this work tonight is a simpler Intellivoice circuit. In the coming days I'll probably revise my NanoVoice circuit to match what I have here and release everything.

I got my boards today. The circuit works, but there's a high-pitched whine that comes out in addition to the speech. I don't yet know why. I'm not yet using the correct daughterboard, though. The one I'm using is a spare ACC daughterboard that generates an MCLKx4 (14.31818 MHz) signal, whereas the correct one is simply a passthrough for all signals. The correct one hasn't arrived yet, but I don't see any reason why an ACC one wouldn't work. I checked out the test points on an oscilloscope and it looks like the speech chip is sending a PWM signal that's getting filtered into the high-pitched whine (I'm testing it with a Space Spartans cartridge). I'm not sure why it's sending data when it should be quiet, but I'll do more testing. One thing I found out through inspecting the normal Intellivoice is that there's an error in the service manual. The schematic is correct, but the bill of materials for register R9 is incorrect. It's listed as 330 ohms when the actual resistor is 180 ohms. I also found out that the eight pull-up resistors on the SPB640's data lines are unnecessary and they're omitted in my Mattel Intellivoice.

Hoping for a reveal video of Time Piliot...

Some of us were born in the 1960's 😁

Will these be available in your store after the expo?

You should know that the NanoVoice is untested. While the schematic conforms to the one in the Intellivoice service manual, I don't have a connector for the cartridge that goes onto the end of the board the way it does on the real Intellivoice. So I've been unable to build and test one. Before you try to build it you might want to wait until I've built and tested the board for my Intellivoice II case. They use the same schematic so if one works so should the other.

I don't even want to think about what this would cost to print... (Why an expansion port? because the ACC actually does have a small expansion header for digital video)

Here is my latest NanoVoice revision. It has better trace routing and makes a change to the design. The original Intellivoice uses 74LS12 chips, which are pretty much made of unobtainium today. I've changed the design to use readily-available 74LS10 chips instead, which also requires removing pull-up resistors R2, R4, and R5. I'm at a loss to understand why Mattel used open-collector 74LS12 chips when push-pull 74LS10 chips result in a simpler design. My Intellivoice II board also uses the same design change. I've double- and triple-checked the schematic and I see no reason why 74LS10 chips wouldn't work, since the output still goes through resistor R1. So KylJoy, how did the print go? NanoVoice_1_5.zip

PM sent. Yikes! Here's hoping for a good recovery!

Would you be able to tell me if I ordered a copy? I've ordered so many homebrews lately that I can't remember. Can I provide you with my town or something so you can check?

I'm still quietly making refinements to the NanoVoice board, as well. Perhaps I'll release what I have.

Board is completed and ordered. In a couple of weeks (hopefully) I'll see how well it fits.

It's getting there. I still need to do the silkscreen. This will probably undergo a few iterations before I have a final version. The main issue is precise positioning of the volume potentiometer and the mounting holes. Once it's finalized I'll release the board design and gerber files. This will use a two-board design like the ECS and the ACC. I've already done the daughterboard that plugs into the Master Component and even ordered one.

Here is a ZIP of the .STL model files for the case. Because of the thin walls, don't expect filament printing to work. According to JLCPCB, it will likely result in sagging and deformation. So I went with Shapeways and their selective laser sintering (SLS) process. For materials I chose their nylon plastic with no finishing. Be warned, the four pieces cost me over $400 to make. The fit, though, is absolutely perfect and I can see no layer lines. The quality is outstanding. Intellivoice_II.zip

The walls are too thin for filament printing (according to one manufacturer), so SLS is required. It's not cheap. I went with Shapeways, and the result is not disappointing. The fit is perfect. Now I have to design a circuit board for it.

Advanced Console Component. Take a look at the "Bird's Nest" thread for more info.

I've fixed several bugs in the processor emulator and added a new instruction: MVIF@ RM, RD. It lets the emulated processor read from its internal font ROM. The documentation has been updated to include the new instruction. Advanced Console Component 20221009.zip

I was thinking about the Program Expander today. Do we know anything about its technical specs? Amount of RAM, any ROM, memory ranges, that sort of thing? It would be pretty simple to adapt part of my Raspberry Pi Pico code from the ACC and have a Pi Pico become a Program Expander.

Email sent. I asked about how you take payment in the email, since I didn't see it in the thread.