VIC 20 Speech Synthesizer Project Part Deux

[Kander2]

I got side tracked on another project, but I'm getting ready to get back to my Votrax SC-01 speech synthesizer project. After spending some time looking at the original schematic and thinking about the best way to do this, 2 things stood out. 1) The original amplifier circuit was poorly designed and not very practical, and 2) a serial interface would be preferable to the expansion port so that it would be portable to any computer. In particular, I'd also like to get it working on a C-64. So now the design question is, what is the best way to implement the interface. Maybe use an Arduino or a Pi. Or do it completely using LSI parts, which would be bulky but fun. Does anybody have any suggestions? One thing to keep in mind is while I was researching the Vic 20 serial bus, I discovered there is a bug in the shift register in the VIA chip. That means you can't use it as part of the design on the VIC 20 side.

When I get the project working, I thought the next step might be to sample the entire SC-01 dictionary and make the data available publicly for anybody who wanted to replicate genuine 1980s speech synthesis.

 

[brain]

I think a Pi or esp32 is overkill. An arduino should work fine, only 8 IO lines or something needed. Here's a project that gets you much of the way there:

Arduino & Votrax "Hello World" - Speech synthesizers

After some fun with the SP0256 (more to come on this) I decided to try the Votrax SC-01. (I found it on Ebay). I followed this schematic: http://kevtris.org/Projects/votraxtnt/index.html I also found a lot of resources here: http://www.redcedar.com/sc01.htm I made this schematic And coded the...

www.polaxis.be

 

[Kander2]

I ran across this really good video that describes not only the software and hardware protocols/problems on the VIC, but also the history of the serial port starting with the PET up through the C-128 (including names of engineers and dates in which things happened) https://www.google.com/search?q=How...e=ive&vld=cid:435622d5,vid:_ANGRSdlygM,st:886

 

[snuci]

In particular, I'd also like to get it working on a C-64. So now the design question is, what is the best way to implement the interface.

As a speech synthesizer aficionado, I have three different commercial Votrax SC-01 based devices that can be used with the VIC-20 as examples, so you can see the range of options, connectivity and expandability.

1. The Protecto VIC-20 Voice Synthesizer cartridge. - This uses the cartridge port. Being a cartridge, this would only work with the VIC-20. This has an audio amplifier with speaker jack and two pots for volume and pitch maybe? I don't recall.



2. Alien Group's Voicebox - This uses the user port. I have the C64 software for this and I have never seen software for the VIC-20 so I'm not even 100% sure it's compatible between the C64 and VIC-20 but it uses the user port that is mostly compatible between the two. The pinouts are NOT identical so that's why I'm not 100% sure this would work on the VIC-20 also.



3. The Votrax Type N Talk - Needs RS-232 Serial cartridge - This is a stand-alone RS-232 serial device made by Votrax that has the SC-01 built in but it's "potted" so I can't show you the internals of the device but here it is. This device can be used with the VIC-20 as illustrated by the Scott Adams Adventure series of games that had speech in them. I used this with an Apple II (via the Super Serial card) and don't remember if I set up a VIC-20 with Commodore's RS-232 cartridge to play one of the Adventure games. I probably did but didn't take a picture. This would have the widest compatibility but you need the serial cartridge for the VIC-20 and the same one for the C64. As noted, it could also be used with other computers like the Apple II or the IBM PC via serial.



Take a look at @kevtris page to see what the board looks like http://kevtris.org/Projects/votraxtnt/index.html

In summary, the options go from "simple and less portable" to "advanced and more portable" so, if you were looking for options, I think this is all of them. Hope this helps and good luck with your project. I look on with interest.

 

[Kander2]

As a speech synthesizer aficionado, I have three different commercial Votrax SC-01 based devices that can be used with the VIC-20 as examples, so you can see the range of options, connectivity and expandability.

1. The Protecto VIC-20 Voice Synthesizer cartridge. - This uses the cartridge port. Being a cartridge, this would only work with the VIC-20. This has an audio amplifier with speaker jack and two pots for volume and pitch maybe? I don't recall.

View attachment 1319247

2. Alien Group's Voicebox - This uses the user port. I have the C64 software for this and I have never seen software for the VIC-20 so I'm not even 100% sure it's compatible between the C64 and VIC-20 but it uses the user port that is mostly compatible between the two. The pinouts are NOT identical so that's why I'm not 100% sure this would work on the VIC-20 also.

View attachment 1319248

3. The Votrax Type N Talk - Needs RS-232 Serial cartridge - This is a stand-alone RS-232 serial device made by Votrax that has the SC-01 built in but it's "potted" so I can't show you the internals of the device but here it is. This device can be used with the VIC-20 as illustrated by the Scott Adams Adventure series of games that had speech in them. I used this with an Apple II (via the Super Serial card) and don't remember if I set up a VIC-20 with Commodore's RS-232 cartridge to play one of the Adventure games. I probably did but didn't take a picture. This would have the widest compatibility but you need the serial cartridge for the VIC-20 and the same one for the C64. As noted, it could also be used with other computers like the Apple II or the IBM PC via serial.

View attachment 1319249

Take a look at @kevtris page to see what the board looks like http://kevtris.org/Projects/votraxtnt/index.html

In summary, the options go from "simple and less portable" to "advanced and more portable" so, if you were looking for options, I think this is all of them. Hope this helps and good luck with your project. I look on with interest.

Thanks for the look at all your boxes. I'm pretty sure at this point the best option is a cheap-o Arduino knock off you can get for under $12. It should be able to easily handle the SC-01 interface, as well as whatever serial interface I end up with. RS232 is a good candidate. The Arduino has several UARTS so I wouldn't have to add anything. I'm also looking at audio amplifiers, and the LM356 seems to be a popular choice, but I don't know if you could get a good sound from a 5 volt supply. There are variants that work well with a 9 volt battery. I'm not sure what to do about that

 

[daver2]

Why does the RS232 serial interface have to be complicated I am thinking to myself?

A simple UART and 5V only RS232 converters should produce the desired interface.

The UART only needs to be uni-directional (receive only) if you can use a handshake bit fir ensuring that the SC01 is ready to receive a new code.

The trick will be finding a small, yet simple, and dumb UART and a baudrate generator.

Dave

 

[Kander2]

Why does the RS232 serial interface have to be complicated I am thinking to myself?

A simple UART and 5V only RS232 converters should produce the desired interface.

The UART only needs to be uni-directional (receive only) if you can use a handshake bit fir ensuring that the SC01 is ready to receive a new code.

The trick will be finding a small, yet simple, and dumb UART and a baudrate generator.

Dave

The UART is built in to the base configuration of the Arduino. It's "free", as it were. The Arduino could handle both the SC-01 and RS232 as-is. I just recently saw an Arduino clone for under $10. On the VIC side I'd need to find an RS232 cartridge on EBAY. That would probably be the biggest expense. I just saw one for almost $200! If I can't find a cheap one, I'd have to build my own