The Texas Instruments LPC Speech Chips are a series of speech synthesizer digital signal processor integrated circuits 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 dissolving in late 2001. The rights to the speech-specific subset of the MSP line, the last remaining line of TI speech products as of 2001, were sold to Sensory, Inc. in October 2001. Theory Speech data is stored through pitch-excited linear predictive coding (PE-LPC), where words are created by a lattice filter, selectably fed by either an excitation ROM (containing a glottal pulse waveform) or an LFSR (linear feedback shift register) noise generator. Linear predictive coding achieves a vast reduction in data volume needed to recreate intelligible speech data. History The TMC0280/TMS5100 was the first self-contained LPC speech synthesizer IC ever made. It was designed for Texas Instruments by Larry Brantingham, Paul S. Breedlove, Richard H. Wiggins, and Gene A. Frantz and its silicon was laid out by Larry Brantingham. The chip was designed for the 'Spelling Bee' project at TI, which later became the Speak & Spell. A speech-less 'Spelling B' was released at the same time as the Speak & Spell. All TI LPC speech chips until the TSP50cxx series used PMOS architecture, and LPC-10 encoding in a special TI-specific format. 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. TI LPC Speech chip family 1978 TMS5100 (TMC0281, internal TI name is '0280' hence chip is sometimes labeled TMC0280): First LPC speech chip. Used a custom 4-bit serial interface using TMS6100 or TMS6125 mask ROM ICs; used on all non-super versions of the Speak & Spell except for the 1980 UK version, which used the TMC0280/CD2801 below. Publicly sold as TMS5100. It was also used on the Byron Petite Electronic Talking Typewriter toy. Superseded in 1979 by TMS5100A and TMS5110. 1980 TMC0280 AKA CD2801: Used in the Speak & Math, Speak & Read, and the TI Language Translator/Language Tutor. Pin, but not function compatible with TMS5100/TMC0280, has a different LPC and slightly different Chirp table. The CD2801/Die revision F fixes an interpolator bug. TMS5100A: Die shrink of TMS5100/TMC0281. Very minor differences in function, uses die rev F, fixing a bug