Texas Instruments LPC Speech Chips

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The Texas Instruments LPC Speech Chips are a series of speech synthesizer DSP ICs created by Texas Instruments beginning in 1978. They continued to be developed and marketed for many years, though the speech department moved around several times within TI, until finally their rights were sold to Sensory Inc. sometime around 2002, and the speech department dissolved. ^[1]

1 Theory
2 History
3 TI LPC Speech chip family:
4 References:

[edit] Theory

Speech data is stored through linear predictive coding (LPC), where words are created by a lattice filter, selectably fed by either an excitation rom or a LFSR noise generator. Linear predictive coding achieves a vast reduction in data volume needed to recreate intelligible speech data.

[edit] History

The TMC0280 was the first self-contained LPC speech synthesizer IC ever made. It was designed for Texas Instruments by George Lawrence "Larry" Brantingham, Paul S. Breedlove, Richard H. Wiggins, and Gene A. Frantz^[2] and its silicon was laid out by Larry Brantingham.^[1] The chip was designed for the 'Spelling Bee' project at TI, which later became the Speak & Spell.^[1] A speech-less 'Spelling B' was released at the same time as the Speak & Spell.^[3]

All TI LPC speech chips until the TSP50cxx series used PMOS architecture, and LPC-10 encoding in a special TI-specific format. ^[4] Chips in the TI LPC speech series were labeled as TMCxxxx or CDxxxx when used by TI's consumer product division, or labeled as TMS5xxx (later TSP5xxx) when sold to 3rd parties.

[edit] TI LPC Speech chip family:

1978:

TMC0281 (AKA TMC0280 AKA TMS5100): Used a custom 4-bit serial interface using TMS6100 or TMS6125 mask rom ICs; used on the original Speak & Spell and its derivatives (i.e. Speak & Math, Speak & Read, Touch & Tell, etc).^[5] It was also possibly used on the Byron Petite Electronic Talking Typewriter^[6]^[1] toy (though it may have been misremembered and the toy may actually use a TMS5110A).

1980?:

TMS5110/TMS5110A: Newer versions of TMS5100, pin compatible; used on two home computer products, and early TI 99/4A speech boards(as the CD2812?). It may have been used on the arcade game Bagman by Valadion Automation, and on the arcade game A.D. 2083 by Midcoin. It also possibly may be used instead of the TMS5100 on the Byron Petite Electronic Talking Typewriter toy.

1981?:

TMC0285 (AKA TMS5200): Added 8-bit parallel FIFO interface; used on the 4th generation Bally pinball tables' Squawk and Talk speech board (part number AS-2518-61), on the Apple II Echo2 card, on some TI 99/4a speech boards, and MAYBE on the arcade game 'Bagman', if it did not use a TMS5110A.
TMS5220: Enhanced 8-bit parallel FIFO interface, added interrupt for data request; used in the IBM PS/2 Speech Adaptor, the BBC Micro, and in several Atari arcade games in the mid 1980s, most notably Gauntlet.

1983:

TMS5220C (later TSP5220CNL): has a single new opcode added to the parallel FIFO interface to control speech rate; otherwise identical, pin-compatible, and a drop-in replacement to the TMS5220.

1985 and onward:

TSP50cxx series: Later CMOS speech chips, all but one use a different encoding (called 'D6') than the TMS5220 did. Some later ones use LPC-12 instead of LPC-10.

The companion devices to ALL versions of the speech chip were the custom 4-bit-interfaced 128Kbit (16KiB) TMS6100NL (AKA TMC0350) and 256Kbit (32KiB) TMS6125NL read-only memories which were mask programmed with words required for a specific product. ^[4] ALL versions of the chip until the TSP50cxx series support them.