TMS5220

The TMS5220 Voice Synthesis Processor (VSP) enables verbal communication with a microcomputer based system.The VSP is fabricated using P-channel MOS technology and is TTL compatible.Speech data that has been compressed using pitch-excited linear predictive coding (LPC), is supplied to the VSP either by the CPU or by direct serial access of a Voice Synthesis Memory (VSM). The VSP decodes this data to construct a time-varying digital filter model of the vocal tract. This model is excited with a digital representation of either glottal air impulses (voiced sounds) or the rush of air (unvoiced soundsl. The output of this model is passed through an eight-bit digital-to-analog converter to produce a synthetic speech waveform.

The TMS5220 has the following features include:(1)high-quality voice communication from a microcomputer system;(2)low-data-rate LPC encoding;(3)low-cost p-channel MOS technology;(4)+5 V and -5 V supplies only;(5)interrupt-based service requests;(6)TTL compatible.This manual describes all VSP timing based on an 8-kHz sample rate (limiting the output frequency to 4 kHz) and a 40-Hz frame rate (the rate at which new speech data of the TMS5220 is fetched and processed). This requires the internal RC oscillator in the VSP to run at 640 kHz. The user has the mask-programmable option of balancing the internal oscillator with a resistor (completing the RC network).

The absolute maximum ratings of the TMS5220 are:(1)any pin with respect to Vss:-20 to +0.3V;(2)storage temperature range:-30 to +125;(3)power disspation:600mW;(4)operating temperature range:0 to +70.The Speak External command allows the CPU to supply speech data to the VSP from some memory other than the VSM. Upon receipt of a Speak External command, the VSP purges the FIFO buffer (BL and BE becomes active [high]) and directs data written into the VSP to this buffer. The VSP idles waiting for the CPU to fill the buffer before speech begins. When the buffer low status becomes false (by the CPU loading a minimum of nine bytes to the FIFO), Talk Status is set and speech synthesis calculations begin using data from the FIFO. Data continues to be taken from the FIFO until a stop code is encountered or the buffer empty abnormal termination occurs. While the Speak External command of the TMS5220 is executing, all data written to the VSP is routed to the FIFO buffer. A Reset command is not recognized as a command.