General Description of Function
Since a self-bias type amplifier of CMOS inverter is contained, an oscillator can be formed by connecting a ceramic
To minimize power dissipation, the oscillator stops oscillating except when key operation is performed.
2. Key entry
Key entry pins KI0 to KI3 and timing signal output pins KO0 to KO7 provide a key matrix of 4 × 8 = 32.
Multi-press of key No. 20 and one of key No. 21, 22, 23 may be done, with no priority given in key entry. When the two
keys are kept pressed, a series of pulses will be output according to each key entry. If multi-press of keys which are not
allowed multi-press is done, no output will be delivered.
3. Data organization
Data consists of 42 bits in all: 13 bits of custom code, 8 bits of key data, and their inverted codes.