WM8962B datasheet(157/295 Pages) WOLFSON

157 / 295 page

WM8962

Rev 4.3

157

BCLK AND LRCLK CONTROL

In master mode, BCLK is derived from DSPCLK via a programmable division set by BCLK_DIV.

In master mode, LRCLK is derived from BCLK via a programmable division set by AIF_RATE.

See “Digital Audio Interface Control” for details of these fields.

In Slave mode, BCLK/LRCLK should not be stopped whilst a DAC to Speaker playback path is active

unless SYSCLK is also stopped. Failure to meet this requirement may result in a DC output at the

speaker outputs, and possible speaker damage.

In Slave mode, if BCLK/LRCLK may stop during DAC to Speaker playback then it is recommended to

use a SYSCLK source that will also stop at the same time as BCLK/LRCLK. It is important to note that

the FLL will continue to run even when its input reference is removed; if the FLL is selected as the

SYSCLK source, then SYSCLK will not stop if BCLK/LRCLK is stopped.

If SYSCLK is stopped whenever BCLK/LRCLK is stopped, or if the audio interface is operating in

Master mode, then no specific action is required in relation to BCLK/LRCLK stopping.

If BCLK/LRCLK may stop during DAC to Speaker playback, with SYSCLK still running, then it is

recommended to disable the Speaker output (see “Output Signal Path”) or to disable the DAC to

Speaker Mixer paths (see “Speaker Output Paths”) before stopping BCLK/LRCLK.

If it is not possible to change the WM8962 settings before BCLK/LRCLK are stopped (ie. the

BCLK/LRCLK inputs may stop unpredictably), then the DAC 2nd order HPF should be enabled in order

to remove DC offsets in the output signal. See “DAC Signal Path Enhancements” for details of this

feature.

CONTROL INTERFACE CLOCKING

may be either the MCLK pin, FLL or PLL3, as described abov

e in the “SYSCLK Control” section.

When SYSCLK_ENA = 1, then an active clock source for SYSCLK must be present for control

interface clocking. If the SYSCLK source is stopped, then SYSCLK_ENA must be set to 0 for control

WM8962B Datasheet(PDF) 157 Page - Wolfson Microelectronics plc