PT2462

V1.6

5 of 13

FUNCTION DESCRIPTION

OSCILLATION CIRCUIT

A self-biased type amplifier is housed by a CMOS Inverter Method. Thus, an oscillation circuit can be constructed by

connecting a ceramic resonator. Please refer to flowing figure for the oscillation circuit diagram.

Unless the keys are being operated, the oscillation is normally stopped. Thus, power consumption is considerably

reduced.

KEY INPUT

A total of 32 keys can be connected by Key Inputs-- KI0 ~ KI3 and Timing Signals -- KO0 ~ KO7. Double Key Operation

is possible for only Key No. 20 in combination with the other keys connected to the KO5 line, namely: Key No. 21, 22 or

23. Thus, only the following key combinations may be used for the double key operation:

• Key No. 20 and 21

• Key No. 20 and 22

• Key No. 20 and 23

There is no order of priority given in key input. This means that keys designated for the double keying operation may be

pressed in any sequence. When two keys (designated for the double key operation) are pressed simultaneously, a

series of pulse is outputted according to each key input. Pressing other keys that are NOT intended for the double key

operation do NOT generate any output.

The Key Matrix is given in the following diagram.