The SP0256-AL2 lives again!

[Karen O]

Hi All,

Years ago I had a General Instruments SP0256-AL2 speech synthesiser chip. It was connected to my 'house computer' (a NIBL based SC/MP system). It performed a number of simple duties, one being the door bell - it would announce 'You have a visitor, mistress'! I remember two things distinctly: 1. It seemed to put emphasis on the 'm' in 'mistress' and sounded peeved - like it was angry at me for something 2. It used to hallucinate, telling me there was someone at the door when there clearly wasn't. The latter turned out to be water getting into the bell push - a problem easily remedied by decreasing the pull-up resistor from 10k to 1k

Recently, I rummaged for that old board but do you think I could find it? It must have been a victim of a sort-out many years back. The NIBL computer is nowhere to be found either (but I made a PIC version a few years back). I longed to hear that monotone disjointed speech once again so started thinking about how I might recreate that venerable IC. Making a digital emulation based on the internal vocal tract model used by this chip would be possible - this guy has reverse engineered the AL2 ROM and even got permission from Microchip (who now own General Instruments intellectual property):

http://spatula-city.org/~im14u2c/sp0256-al2/

But that seemed like an awful lot of work. It would be well worth it though. My answer was found when I found this helpful guy, who has sampled the complete allophone set of the chip:

http://little-scale.blogspot.co.uk/2...mple-pack.html

He distributes these samples under a 'Creative Commons Attribution-Noncommercial 3.0 Unported License'. How legal that is with respect to Microchip I don't know. I assume that, since Microchip are happy for the ROM contents to be distributed, they at least won't get upset about hobbyists using samples of the allophones for non-commercial purposes.

Anyway, I've loaded the allophones onto an SD card and made myself a little speech synthesis board, driven by a PIC16F627. It accepts allophones over a serial link at 1200 baud and has an 80 allophone buffer (there is no flow control, other than a signal to an LED which lights while the unit is speaking). I've also added measures to ensure smooth transitions between allophones so that it doesn't sound so much like samples stitched together.

I think it sounds quite close to the real IC, though it has been a VERY long time since I last heard speech from that IC. I'd upload a sample recording, but sound doesn't appear to be among the file types supported. Maybe I should hide it in a ZIP?

[Ti Pwun]

Excellent!

I built a speech module for my ZX81 using that IC, back in the day - had a lot of fun with it. I think it was in a Maplin mag, if I remember correctly.

I remember staying up all night etching and building the PCB and then eagerly waiting for my father to get up for work at 7am.

"Good morning... I am a clever computer", I had it announce as he entered the room. I think I was 14 then.

Happy days. I still have the IC somewhere and the original packaging with datasheet. Not sure what happened to the PCB I made, or indeed the ZX81, but I did keep the IC.

[Dekatron]

Nice!

I love that chip, it was the first circuit that I ever built connected to a computer and we had a lot of fun with it, especially since we tried to use it to speak Swedish, it had a very clear English accent!

It is actually still available on Ebay, I've bought a bunch, both original in the Archer package and some from Chinese sellers and they all work, I can't say anything about the quality of those chips from the Chinese sellers but they work. The only hard thing to find nowadays is that 3.12 MHz crystal.

/Martin

[Radio Wrangler]

Coincidentally, I passed the old GI MOS semiconductor plant in Glenrothes yesterday, and the Pico Electronics plant which spawned it. Pico is believed to have sold microprocessor devices for calculators just fractionally before Intel. It was closed down as an Elliot subsidiary when GEC was formed and had built a new plant at Chelmsford. The Pico people looked for a new employer and found General Instruments.

So the chips have far outlived the fab.

David

[RogerEvans]

I too had one of these but I had forgotten about it until I saw this thread. I had a Dragon 32 home computer, 6809 processor which was great but only 256x192 monochrome graphics. I wrote a reasonably decent flight simulator, all hand assembled code typed in in hex. The synthesiser was supposed to do the stall warning announcement and call out the heights on the landing approach, it worked but the sound quality was poor and I lost interest. Happy days!

Roger

[SiriusHardware]

I still have one of these in the form of a boxed 'Currah uSpeech' unit for my ZX Spectrum. At one point it was involved in a control-by-radio experiment (Over CB, which was the only 'long range' radio equipment available to me at the time).

DTMF encoder and decoder ICs still weren't very common or cheap at the time so an NE567? single tone detector IC was used and the Spectrum was programmed to recognise morse characters and to turn various outputs of a connected 8255 I/O port IC on and off in response to those characters. It was, basically, an early experiment in remote home control.

The system gave a spoken acknowledgement (back over radio) that it had received the command request and carried it out - that was what the uSpeech was used for.

The useful operating range of the system was, ironically, limited by the use of the Spectrum as the controller because it generated quite a lot of interference on HF, including 27Mhz. Beyond a certain range, the remote transmitter was unable to burn through the local interference being generated by the computer.

[G6Tanuki]

I recall an afternoon spent in a lab at Exeter university, with a BBC micro and one of those chips.

We were really proud when we got it to 'speak' with a noticeable Devon accent.

[Karen O]

Okay, here's a ZIP file containing an MP3 recording of the speech synth in action.

[Ti Pwun]

That brought back memories. I remember the actual chip sounding much better, though. Although I do remember having to make up the words in a strange way in order to get them to sound good.

[Karen O]

I remember that getting this chip's speech to sound right was a matter of patient fiddling with allophones. When I tried to make it say 'mistress' neither of the 't' sounds (TT1, TT2) came even close. In the end I used the JH allophone.

[Ti Pwun]

Yep, definitely remember doing a lot of that.