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RL78/D1A User's Manual: Hardware - Renesas

RL78/D1A User's Manual: Hardware - Renesas

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Under development<br />

Preliminary document<br />

Specifications in this document are tentative and subject to change.<br />

<strong>RL78</strong>/<strong>D1A</strong> CHAPTER 17 SOUND GENERATOR<br />

CHAPTER 17 SOUND GENERATOR<br />

The Sound Generator generates an audio-frequency tone signal and a high-frequency pulse-width modulated (PWM)<br />

signal. The duty cycle of the PWM signal defines the volume.<br />

By default, the two signal components are routed to separate pins. But both signals can also be combined to generate<br />

a composite signal that can be used to drive a loudspeaker circuit.<br />

17.1 Overview<br />

The Sound Generator consists of a programmable square wave tone generator and a programmable pulse-width<br />

modulator.<br />

Features<br />

Programmable sound frequency<br />

Activation of the automatic logarithmic decrement function for linear volume decreasing without CPU instruction<br />

Programmable volume level (9 bit resolution)<br />

Wide range of PWM signal frequency<br />

Sound can be stopped or retriggered (even if ALD is switched on)<br />

Composite or separated frequency/volume output for external circuitry variation<br />

Variable PWM level for generation of the SGTIO interrupt (noise dependent end interrupt)<br />

<strong>Hardware</strong>-optimized update of frequency and volume to avoid audible artifacts<br />

R01UH0317EJ0004 Rev. 0.04 997<br />

Feb. 22, 2013

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