4 ms·

This is a very weird and specific question I know, but I figured I'd ask anyway because you seem to have experience with this chip. In 'Halt and Catch Fire,'[0

by yzzxy 12y ago

This is a very weird and specific question I know, but I figured I'd ask anyway because you seem to have experience with this chip. In 'Halt and Catch Fire,'[0] one of the characters loads his children's names onto a Speak n Spell's memory. He's portrayed as a very talented engineer, and a lot of the show seems to be pretty true to the tech. My question is, would this be possible for someone with a lot of patience, experience, and a home workshop at that point, or is it an apocryphal story? [0] A last TV season about an early PC startup in the 80s

fit2rule 12y ago
In the show, one of the characters works for TI, so has access to all kinds of internal tools for the task. Its not unrealistic to imagine they could do it; details were omitted though, as to how they did it.
analog31 12y ago
There's a good chance that something like the Speak n Spell during that era stored its program in mask-programmed ROM. That's where the program is fabricated into the IC itself, and specified when you order a batch of chips.
kens 12y ago
I'd say its possible but unlikely that someone reprogrammed their Speak n Spell. The first tricky thing is the TMS5100 voice synthesis chip uses a complex LPC-10 encoding to encode the sound with a very low bit rate (1100 bits/sec). Basically it's modeling the filter characteristics of the vocal tract. So the first problem is you have to convert your audio signal into this representation, which is going to be really, really hard unless you have access to the TI system that does this conversion. The second problem is the speech data is stored in a TMS6100 ROM which is kind of a strange chip: the 14-bit address is loaded 4 bits at a time, and then the ROM steps sequentially through memory from there. The point is that you can't reprogram this chip (since it's a ROM), and emulating it with a standard EPROM would be a big pain. I should point out that I don't have firsthand experience with these chips (apart from using a Speak n Spell years ago). But I happen to have been studying them in detail a couple weeks ago for random reasons. For more information on this chipset, the datasheets are at http://www.datasheet-pdf.com/datasheet-html/T/M/S/TMS5100_TexasInstruments.pdf.html http://www.datasheet-pdf.com/datasheet-html/T/M/S/TMS5100_Te... and http://www.ti99.com/exelvision/website/telechargement/tms6100-80-data-manual.pdf http://www.ti99.com/exelvision/website/telechargement/tms610... I just did a search and found someone who hacked new words into a Speak n Spell a couple years ago. But he needed to use a CPLD (like a FPGA) to simulate the ROM, and a Windows LPC encoding program, so this wouldn't have been possible in the 80s. http://furrtek.free.fr/index.php?a=speakandspell&ss=1&i=2 http://furrtek.free.fr/index.php?a=speakandspell&ss=1&i=2
- yzzxy 12y ago
  Hmm... his wife worked at TI as an engineer IIRC. So it's a tenuous, unlikely, made-for-tv kind of possibility indeed. It's gotten me interested in circuit bending again, however.
- dgalloway 12y ago
  Looked it up and that show is set in 1983 so it does seem rather implausible but not impossible of course. :) Here's a good run through using the Windows LPC encoding program. http://www.youtube.com/watch?gl=GB&v=wVDE-6TtmFQ http://www.youtube.com/watch?gl=GB&v=wVDE-6TtmFQ

by yzzxy 12y ago

fit2rule 12y ago

In the show, one of the characters works for TI, so has access to all kinds of internal tools for the task. Its not unrealistic to imagine they could do it; details were omitted though, as to how they did it.

analog31 12y ago

There's a good chance that something like the Speak n Spell during that era stored its program in mask-programmed ROM. That's where the program is fabricated into the IC itself, and specified when you order a batch of chips.

kens 12y ago

I'd say its possible but unlikely that someone reprogrammed their Speak n Spell. The first tricky thing is the TMS5100 voice synthesis chip uses a complex LPC-10 encoding to encode the sound with a very low bit rate (1100 bits/sec). Basically it's modeling the filter characteristics of the vocal tract. So the first problem is you have to convert your audio signal into this representation, which is going to be really, really hard unless you have access to the TI system that does this conversion. The second problem is the speech data is stored in a TMS6100 ROM which is kind of a strange chip: the 14-bit address is loaded 4 bits at a time, and then the ROM steps sequentially through memory from there. The point is that you can't reprogram this chip (since it's a ROM), and emulating it with a standard EPROM would be a big pain. I should point out that I don't have firsthand experience with these chips (apart from using a Speak n Spell years ago). But I happen to have been studying them in detail a couple weeks ago for random reasons. For more information on this chipset, the datasheets are at http://www.datasheet-pdf.com/datasheet-html/T/M/S/TMS5100_TexasInstruments.pdf.html http://www.datasheet-pdf.com/datasheet-html/T/M/S/TMS5100_Te... and http://www.ti99.com/exelvision/website/telechargement/tms6100-80-data-manual.pdf http://www.ti99.com/exelvision/website/telechargement/tms610... I just did a search and found someone who hacked new words into a Speak n Spell a couple years ago. But he needed to use a CPLD (like a FPGA) to simulate the ROM, and a Windows LPC encoding program, so this wouldn't have been possible in the 80s. http://furrtek.free.fr/index.php?a=speakandspell&ss=1&i=2 http://furrtek.free.fr/index.php?a=speakandspell&ss=1&i=2

yzzxy 12y ago
Hmm... his wife worked at TI as an engineer IIRC. So it's a tenuous, unlikely, made-for-tv kind of possibility indeed. It's gotten me interested in circuit bending again, however.
dgalloway 12y ago
Looked it up and that show is set in 1983 so it does seem rather implausible but not impossible of course. :) Here's a good run through using the Windows LPC encoding program. http://www.youtube.com/watch?gl=GB&v=wVDE-6TtmFQ http://www.youtube.com/watch?gl=GB&v=wVDE-6TtmFQ