WM9711 Datasheet, PDF (38/66 Pages) Wolfson Microelectronics plc – LOW POWER AUDIO CODEC FOR PORTABLE APPLICATIONS

WM9711L
COMP2 DELAY FUNCTION
Production Data
COMP2 has an optional delay function for use when the input signal is noisy. When COMP2 triggers
and the delay is enabled (i.e. COMP2DEL is non-zero), then GPIO bit 14 does not change state
immediately, and no interrupt is generated. Instead, the WM9711L starts a delay timer and checks
COMP2 again after the delay time has passed. If COMP2 is still active, then the GPIO bit is set and
an interrupt may be generated (depending on the state of the GW14 bit). If COMP2 is no longer
active, the GPIO bit is not set, i.e. all register bits are as if COMP2 had never triggered.
Note: If COMP2 triggers while the WM9711L is in sleep mode, and the delay is enabled, then the
device starts the on-chip crystal oscillator in order to count the time delay.
COMP2
TRIGGERS
C2W?
0
1
COMP2
DEL?
non-zero
START TIMER
END
WAIT
time=COMP2DEL
000
SHUT DOWN
TIMER
COMP2?
Active
SET GI14
Inactive
END
[FALSE ALARM]
END
Figure 5 COMP2 Delay Flow Chart
w
PD Rev 4.1 April 2004
38