UPD9930 datasheet(11/78 Pages) NEC

11 / 78 page

µPD9930

TIMER

RINGER

REC10

RAUXO

(Tone output)

RINGER

RAUXO

(Tone output)

2.1.4 Audio Digital Accessory Output

(1) Ringer output (RINGER pin)

•

Outputs rectangular waves of the same signal frequency as tone signal frequency.

•

The output is controlled by turning off power to the output buffer with a control register.

Figure 2-3 RINGER Output

The RINGER signal tends to bounce when the tone output (RAUXO) signal crosses its zero level, and this

tendency increases as the tone output gain decreases (lower than 0 dB).

When using RINGER pin, tune the tone output gain by TNGCR (Tone gain control register) to 0 dB.

(2) Timer (tone interval) output (TIMER pin)

Outputs rectangular waves of the same pattern as the tone signal interrupt pattern. This is used to make the

LED blink in synchronization with the ringer tone.

Figure 2-4 Digital Accessory Output Waveform

2.1.5 Audio Digital Signal Processor

Send signal digital BPF processing, receive signal digital LPF processing, transmission level (digital gain)

control, and tone generation processing.

(1) Voice send signal digital gain fine adjustment function

Performs gain fine adjustment for voice send signal by digital coefficient multiplication. Together with prefilter

gain adjustment, fine adjustment is possible at a width of 5.8 dB.

(2) Voice receive signal digital gain fine adjustment function

Performs fine adjustment of gain for voice receive signal by digital coefficient multiplication.

(3) Tone generation function

Generates single-tone and dual-tone audible signals. Tone frequency, interrupt pattern, gain, generation/stop

can be controlled by microcontroller command. GSM triple tone can be generated by special command.

UPD9930 Datasheet(PDF) 11 Page - NEC