Production Data
WM9715L
The WM9715L has two on-chip comparators that can be used to implement a battery alarm function,
or other functions such as a window comparator. Each comparator has one of its inputs tied to any
one of three device pins and the other tied to a voltage reference. The voltage reference can be
either internally generated (VREF = AVDD/2) or externally connected on AUX4 (pin 12).
The comparator output signals can be used to send an interrupt to the CPU via the GENIRQ pin,
and / or to wake up the WM9715L from sleep mode (see “Interrupt Control” for details).
REGISTER
ADDRESS
BIT
15
LABEL
DEFAULT
DESCRIPTION
4Eh
58h
CP1
1
COMP1 Polarity (see also “Interrupt Control”)
0: Alarm when COMP1 voltage is below VREF
1: Alarm when COMP1 voltage is above VREF
COMP2 Polarity (see also “Interrupt Control”)
0: Alarm when COMP2 voltage is below VREF
1: Alarm when COMP2 voltage is above VREF
Low Battery Alarm Delay
14
CP2
1
0
15:13 COMP2
DEL
000: No delay
001: 0.17s (213 = 8192 AC-Link frames)
010: 0.34s (214 = 16384 AC-Link frames)
011: 0.68s (215 = 32768 AC-Link frames)
100: 1.4s (216 = 65536 AC-Link frames)
101: 2.7s (217 = 131072 AC-Link frames)
110: 5.5s (218 = 262144 AC-Link frames)
111: 10.9s (219 = 524288 AC-Link frames)
Table 32 Comparator Control
REGISTER
ADDRESS
BIT
14
LABEL
DEFAULT
DESCRIPTION
5Ch
C1REF
0
Comparator 1 Reference Voltage
Additional
Analogue
Functions
0
1
VREF = AVDD/2
WIPER/AUX4 (pin 12)
13:12 C1SRC
00
Comparator 1 Signal Source
00
AVDD/2 when C1REF=’1’. Otherwise
comparator 1 is powered down
01
10
11
COMP1/AUX1 (pin 29)
COMP2/AUX2 (pin 30)
BMON/AUX3 (pin 31)
11
C2REF
C2SRC
0
Comparator 2 Reference Voltage
0
1
VREF = AVDD/2
WIPER/AUX4 (pin 12)
10:9
00
Comparator 2 Signal Source
00
AVDD/2 when C2REF=’1’. Otherwise
comparator 2 is powered down
01
10
11
COMP1/AUX1 (pin 29)
COMP2/AUX2 (pin 30)
BMON/AUX3 (pin 31)
Table 33 Comparator Reference and Source Control
PD Rev 4.0 December 2007
49
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
