MHT Speech Synthesizer

MHT Speech Synthesizer aka Sintetizador de voz (MHT Ingenieros)

Probably uses a SP0256(-AL2?) chip.

• The I/O addresses are unknown.
• The clock frequency is unknown (as shown on the photo, it uses an oscillator, ie. NOT the 4MHz signal on the expansion port).

Port ????h READ:

 bit?   Status 1 (0=Speech Busy, 1=Ready/Halted)   (SBY Pin, Speech Busy)
 bit?   Status 2 (0=Ready to Receive Data, 1=Busy) (/LRQ Pin, Load Request)
 bit?-? Not used (garbage, probably usually highz)

Port ????h WRITE:

 bit7-6 Reserved (should be be zero, though SP0256 Pins10-11 are GNDed)
 bit5-0 Allophone number               ;data can be send when Status.Bit?=0

• SP0256
• SP0256 Voice Generator
• SP0256 Instruction Set
• SP0256 Allophones
• SP0256 Pin-Outs

Now, thanks to Jose Leandro, the hardware specialist of the spectrum, with his famous page :

http://trastero.speccy.org/cosas/JL/JL.htm

We can know more about this hardware.

• MHT Speech
• 

  Outside

• 

  Inside

• 

  Component Side

• 

  Solder Side

• MHT Speech Synthesizer Layout, thanks to Jose Leandro
• 

  PCB Back

• 

  PCB Front

• 

  PCB Chips

• 

  PCB Complete

• 

  Layout

The part numbers on the chips seem to be scratched-off (or covered by paint, or is it just old glue from stickers?).

The "GI" logo on the large chip implies that it is the popular General Instrument SP0256 speech chip, probably the standard -AL2 version (the ending L2 may be still visible? not sure there - on the photo it vanishes under the pot axis).

The clock frequency of the oscillator isn't visible (from the perspective from where the photos were taken).

The GNDed pins somewhat confirm that it is a SP0256 (Pin1=Supply GND, Pin10,11=A8,A9, ie. only 6bit allophone numbers used).

Caution - There are two files, Image:MHT-sintetizdor_de_voz-005.jpg and Image:MHT-sintetizdor_de_voz-008.jpg circulated in internet.

Despite of their filesnames, they do NOT show a MHT speech synthesizer - please do not add these files to this page!

The hardware shown on those pics is an ARA Video Digitizer, nothing to do with MHT Speech.

• Software of Sintetizador de voz (MHT Ingenieros).zip
• SP0256-AL2 ROM (caution - the bytes in the file are in reversed bit-order, ie. the "Target" values are unreversed, all other opcodes and parameters are reversed)

• Amstrad SSA-1 Speech Synthesizer (SP0256 based)
• Dk'tronics Speech Synthesizer (SP0256 based)
• TMPI speech synthetizer (MEA8000 based)
• Software Speech Synthesizers (Software based)