Currah
Encyclopedia
Currah was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 peripheral
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....

 manufacturer, famous mainly for the speech synthesis
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...

 cartridges it designed for the ZX Spectrum
ZX Spectrum
The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd...

, Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...

, and other 8-bit home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...

s of the 1980s.

Currah μSource for the ZX Spectrum

Currah μSource from Quadhouse. In a self-contained ROM cartridge it has a full-function-two-pass macro assembler, Forth and a debugger, all of which can interact with Basic. It is also compatible with Interface 1.
http://www.sincuser.f9.co.uk/048/usource.htm

Currah Microspeech for the ZX Spectrum

The Currah Microspeech (or μSpeech) unit plugged into the expansion port on the back of the ZX Spectrum. Additional leads were provided to feed the sound and UHF
Ultra high frequency
Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...

 signal from the computer into the unit. The TV aerial lead plugged into the unit and speech sounds were added into the UHF signal generated by computer.

By default, the unit "spoke" every key-press the user made, even the direction keys which came out as "CURSOR". This could be controlled by a reserved variable KEYS. Typing
LET KEYS=0
would turn this feature off.

Programming speech

Specific words and phrases could be spoken by assigning a value to the reserved string variable S$. This was interpreted letter-by-letter unless brackets were used to denote other allophone
Allophone
In phonology, an allophone is one of a set of multiple possible spoken sounds used to pronounce a single phoneme. For example, and are allophones for the phoneme in the English language...

s. A simple example would be "(dth)is", (dth) representing the voiced dental fricative
Voiced dental fricative
The voiced dental non-sibilant fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound, eth, is . The symbol was taken from the Old English letter eth, which could stand for either a voiced or unvoiced...

 /ð/. Sixty-three allophones were provided. Rudimentary pitch modulation could be achieved by altering the case of the letters—upper case letters being pronounced at a slightly higher pitch.

A more complex example:
5 REM OKAY WISEGUY THIS IS IT
10 LET a$=" (oo)K (AA)"
20 LET b$="w(ii)z (ggg) (ii),"
30 LET c$=" (dth)is iz it"
40 LET S$=a$+b$+c$

Technical details

The unit contained a ULA which worked on a WRITE command from the microprocessor, a ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...

 containing the keyword speech patterns, and an SP0256-AL2 speech processor. It also contained a clock for clear speech and an audio modulator to transfer the sound to the TV lead. A small adjustment screw was provided, to allow fine tuning of the audio output.

The unit allocated itself the top 256 bytes of memory at switch-on and moved down the USR graphics and RAMTOP. This made it incompatible with some programs, particularly games, which use that space for machine code.

For cost reasons, the unit did not provide for daisy-chaining
Daisy chain
Daisy chain may refer to a daisy garland created from daisy flowers, the original meaning and the one from which the following derive by analogy:*Daisy chain *Daisy chain *Daisy chain...

 of further devices on the computer's expansion port. Sadly, most joystick
Joystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...

 interface
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

 manufacturers took the same approach, meaning that you could not have a joystick and the MicroSpeech unit plugged in at the same time.

Some game software will not run while this unit is attached to a Spectrum, notably the RoboCop
RoboCop (video game)
RoboCop is a 1987 action movie set in a crime-ridden Detroit, Michigan in the near future. RoboCop centres a police officer that is brutally murdered and subsequently re-created as a super-human cyborg, otherwise known as a "RoboCop"...

arcade game
Arcade game
An arcade game is a coin-operated entertainment machine, usually installed in public businesses such as restaurants, bars, and amusement arcades. Most arcade games are video games, pinball machines, electro-mechanical games, redemption games, and merchandisers...

 port.

Booty (Firebird Software Ltd) actually detected the presence of a MicroSpeech unit and presented the user with a completely different game Alternate Game to that which would be played if the MicroSpeech unit was not present Normal Game.

History

Currah was acquired by dk'tronics
DK'Tronics
dk'tronics were a software and hardware company during the 1980s. They primarily made peripherals for the ZX Spectrum and Amstrad CPC but also released video games for the Spectrum, Commodore 64, Commodore Vic 20, BBC Micro, Memotech, MSX and Amstrad platforms....

 in 1985. dk'tronics continued to manufacture the MicroSpeech unit, and many of their software titles (such as Maziacs
Maziacs
Maziacs is an action adventure maze video game published by dk'tronics in 1983 for the ZX Spectrum, Commodore 64 and MSX.-History:Maziacs, written by Don Priestley, was based on his earlier ZX81 game Mazogs which was published by Bug Byte in 1982...

and Zig Zag
Zig Zag (video game)
Zig Zag is a maze video game written by Ed Hickman and published by dk'tronics in 1984. It was released for the ZX Spectrum and the Commodore 64.-Gameplay:...

) supported it.

External links

  • Review of the product at CRASH
    CRASH (magazine)
    Crash was a magazine dedicated to the ZX Spectrum home computer. It was published from 1984 to 1991 by Newsfield Publications Ltd until their liquidation, and then until 1992 by Europress.-Development:...

    magazine
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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