WM8998 datasheet(80/307 Pages) WOLFSON

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WM8998

Production Data

PD, October 2014, Rev 4.0

TONE GENERATOR

The WM8998 incorporates two 1kHz tone generators which can be used for ‘beep’ functions through

any of the audio signal paths. The phase relationship between the two generators is configurable,

providing flexibility in creating differential signals, or for test scenarios.

Tone Generator 1 (04h)

Tone Generator 2 (05h)

1kHz

Tone Generator

TONE1_ENA

TONE2_ENA

TONE_OFFSET

TONE_RATE

TONE1_OVD

TONE1_LVL

TONE2_OVD

TONE2_LVL

Figure 30 Digital Core Tone Generator

The tone generators can be selected as input to any of the digital mixers or signal processing

functions within the WM8998 digital core. The bracketed numbers in Figure 30, eg. “(04h)” indicate

the corresponding *_SRCn register setting for selection of that signal as an input to another digital

core function.

The sample rate for the tone generators is configured using the TONE_RATE register - see Table 19.

Note that sample rate conversion is required when routing the tone generator output(s) to any signal

chain that is asynchronous and/or configured for a different sample rate.

The tone generators are enabled using the TONE1_ENA and TONE2_ENA register bits as described

in Table 16. The phase relationship is configured using TONE_OFFSET.

The tone generators can also provide a configurable DC signal level, for use as a test signal. The DC

output is selected using the TONEn_OVD register bits, and the DC signal amplitude is configured

using the TONEn_LVL registers, as described in Table 16.

WM8998 Datasheet(PDF) 80 Page - Wolfson Microelectronics plc