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.
