WM8524

Production Data

w

PD, Rev 4.1, October 2011

16

POWER UP AND DOWN CONTROL

The MCLK, BCLK and MUTE

¯¯¯¯¯ pins are monitored to control how the device powers up or down, and

this is summarised in Figure 9 below.

Off

Standby

Enabled

BCLK Enabled

MUTE=1

MUTE=0

BCLK

Disabled

MCLK

Disabled

MCLK Enabled

BCLK Enabled

MUTE=0

MCLK Enabled

BCLK Enabled

MUTE=1

MCLK

Disabled

Figure 9 Hardware Power Sequence Diagram

Off to Enable

To power up the device to enabled, start MCLK and BCLK and set MUTE

¯¯¯¯¯ = 1.

Off to Standby

To power up the device to standby, start MCLK and BCLK and set MUTE

¯¯¯¯¯ = 0. Once the

device is in standby mode, BCLK can be disabled and the device will remain in standby

mode.

Standby to Enable

To transition from the standby state to the enabled state, set the MUTE

¯¯¯¯¯ pin to logic 1 and start BCLK.

Enable to Standby

To power down to a standby state leaving the charge pump running, either set the MUTE

¯¯¯¯¯ pin to logic

0 or stop BCLK. MCLK must continue to run in these situations. The device will automatically mute

and power down quietly in either case.

Note:

It is recommended that the device is placed in standby mode before sample rate change if the sample rate changes more than

once in 1026 LRCLK periods, as detailed in Digital Audio Data Sampling Rates on page 14.

Enable to Off

To power down the device completely, stop MCLK at any time. It is recommended that the device is

placed into standby mode as described above before stopping MCLK to allow a quiet shutdown.

For the timing of the off state to enabled state transition (power on to audio out timing), and the

enabled state to standby state transition (the shutdown timing), please refer to WTN0302.