T6658A

The T6658A has the following features including Single chip voice recognition LSI;A microphone can be directly connected;Manual control by the keyboard 0r CPU control is possible;External RAM for registration can be connected directly;On-chip 400 kHz ceramic oscillation circuit,also RC oscillation is provided.(mask option;T6658B);Input/Output is LS-TTL compatible (except some input terminals);67-pin thin flat package.

The T6658A is a single chip voice recognition LEI with the on-chip analog interface,voice analysis,recognition process and system control functions.A voice recognition system can be composed with an external microphone,RAM and keyboard. The operation of the T6658A is divided broadly into two modes;the registration mode and recognition mode.  On the other hand,there are two methods for controlling the T6658A; the manual mode by means of an external keyboard and the CPU mode in which the T6658A is controlled by another microcomputer.Further,there is the stand-by mode to stop the operation of the T6658A to reduce power consumption.  The registration and recognition modes are described in this section.The registration mode is a mode to register words which are desired to be recognized and stored themin an external RAM.  Words must always be registered prior to recognition.

The recognition mode is a mode to actually recognize words.In this recognition mode, the T6658A starts the recognition operation automatically whenever voice is input.Even after the T6658A has been placed in the recognation mode, it is possible to return to the registration mode again and make the addition and/or change of words to be registered or already registered words.In the stand-by mode, the operation of the T6658A is completely stopped but contents of words registered in the external RAM are kept unchanged.It is possible to shift to this stand-by mode from both the recognition and registration modes.However,in case of the manual mode and registration mode,current flows into the built-in pull-down resistors and therfore, to operate the T6658A in the manual mode it is necessary to shift from the recognition mode to the stand-by mode.