Cypress S6J3200 Series, Manual

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CHAPTER 19:Sound Waveform Generator
460 S6J3200 Series Hardware Manual Document Number: 002-04852 Rev. *G
1.
Overview
This section gives a brief overview of the sound waveform generator (SWFG).
Also refer to the chapter of "Sound System configuration" how to configure the SWFG..
The SWFG is a function that generates and outputs a Pulse Code Modulation (PCM) sound source using
simple software settings.
Table 1-1
Feature Description
Output frequency 64 types (scales) settable by software.
Output waveform Sine wave, sawtooth wave, and square wave selectable by software.
Volume control (fade in and fade out
functions) Seamless fade in and fade out by software are supported immediately
after generation starts and immediately before generation ends.
Sound time A time from 1 ms to 4 seconds selectable by software.
Number of output channels Simultaneous output of up to five different sound sources is supported.
Interrupt Completion of sound source output generates an interrupt.
Consecutive setting
While a sound source is being generated, register settings for generating
the next sound source can be configured.
Output data pattern
Generates a 16-bit PCM (Pulse Code Modulation) sound source XXXX
internally by the SWFG, expands it to 32 bits, and outputs it (AHB master
interface). The output data pattern can be selected by register settings.
− XXXX_XXXX: Upper and lower 16 bits are the same data.
− 0000_XXXX: Only lower 16 bits of data (Upper 16 bits are zero.)
− XXXX_0000: Only upper 16 bits of data (Lower 16 bits are zero.)
Output sampling rate 48 kHz (fixed).
FIR filter
A Low Pass Filter is provided to eliminate sawtooth and square waveform
overtones. The filtering cutoff frequency is selectable.
Notes:
−
Theoretically, system noise tends not to be a factor in the case of a sine wave that contains single
frequency components. Use of a sine wave is particularly recommended when sound source
mixing or other processes are performed by other functions.
−
Interrupts due to factors other than sound source output completion are also supported. For
details, see 3.2.
−
Continuous sound (continuation of the same sound or different sound) can be generated by
configuring the settings of the next sound's parameters while a sound source is being generated.
However, when repeatedly generating the same sound the same parameters settings need to be
configured.
−
Use of the Low Pass Filter can be disabled. When using the Low Pass Filter, the optimum cutoff
frequency should be decided upon sufficient evaluation of sound quality on the system.