wm8918 Wolfson Microelectronics plc, wm8918 Datasheet - Page 38

• Manufacturer Part Number: wm8918
• Description: Ultra Low Power Dac For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8918
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A clock is required for the digital filtering function, and the DC Servo must also be running. This
requires:
Any MICBIAS Current Detect event (accessory insertion/removal or hookswitch press/release) which
happens while one or more of the clocking criteria is not satisfied (for example during a low power
mode where the CPU has disabled MCLK) will still be detected, but only after the clocking conditions
are met. An example is illustrated in Figure 25, where the mic is inserted while MCLK is stopped.
Figure 25 MICBIAS Detection events without MCLK
Mic insertion event
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•
•
MCLK is present or the FLL is selected as the SYSCLK source in free-running mode
CLK_SYS_ENA = 1
DCS_ENA_CHAN_n is enabled (where n = 0, 1, 2 or 3)
MCLK
GPIO
IRQ
happens at any time
(1) insertion event
during this period
t
DET
(2) insertion indicated t
after MCLK re-started
PD, Rev 4.0, September 2010
Production Data
DET
38