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Last modified on 6 May 2014, at 07:21

MHT Speech Synthesizer

Revision as of 07:21, 6 May 2014 by Cpcmaniaco (Talk | contribs)

MHT Speech Synthesizer aka Sintetizador de voz (MHT Ingenieros)

Technical

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

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.

Pictures

  • 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.

Downloads

  • No included driver/sample program...?
  • 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)

Other CPC Speech Synthesizers