wm9712l Wolfson Microelectronics plc, wm9712l Datasheet - Page 49

• Manufacturer Part Number: wm9712l
• Description: Ac?97 Audio And Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

Production Data
w
The WM9712L 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 are passed to the GPIO logic block (see “GPIO and Interrupt Control”
section), where they can be used to send an interrupt to the CPU via the AC-Link or via the IRQ pin,
and / or to wake up the WM9712L from sleep mode. COMP1/AUX1 (pin 29) corresponds to GPIO bit
15 and COMP2/AUX2 (pin30) to bit 14.
Table 35 Comparator Control
Table 36 Comparator Reference and Source Control
4Eh
58h
5Ch
Additional
Analogue
Functions
REGISTER
REGISTER
ADDRESS
ADDRESS
15
14
15:13
14
13:12
11
10:9
BIT
BIT
CP1
CP2
COMP2
DEL
C1REF
C1SRC
C2REF
C2SRC
LABEL
LABEL
1
1
0
0
00
0
00
DEFAULT
DEFAULT
COMP1 Polarity (see also “GPIO and Interrupt
Control”)
0: Alarm when COMP1 voltage is below VREF
1: Alarm when COMP1 voltage is above VREF
COMP2 Polarity (see also “GPIO and Interrupt
Control”)
0: Alarm when COMP2 voltage is below VREF
1: Alarm when COMP2 voltage is above VREF
Low Battery Alarm Delay
000: No delay
001: 0.17s (2
010: 0.34s (2
011: 0.68s (2
100: 1.4s (2
101: 2.7s (2
110: 5.5s (2
111: 10.9s (2
Comparator 1 Reference Voltage
Comparator 1 Signal Source
Comparator 2 Reference Voltage
Comparator 2 Signal Source
00
01
10
11
00
01
10
11
0
1
0
1
VREF = AVDD/2
WIPER/AUX4 (pin 12)
AVDD/2 when C1REF=’1’. Otherwise
comparator 1 is powered down
COMP1/AUX1 (pin 29)
COMP2/AUX2 (pin 30)
BMON/AUX3 (pin 31)
VREF = AVDD/2
WIPER/AUX4 (pin 12)
AVDD/2 when C2REF=’1’. Otherwise
comparator 2 is powered down
COMP1/AUX1 (pin 29)
COMP2/AUX2 (pin 30)
BMON/AUX3 (pin 31)
16
17
18
13
14
15
19
= 65536 AC-Link frames)
= 131072 AC-Link frames)
= 262144 AC-Link frames)
= 8192 AC-Link frames)
= 16384 AC-Link frames)
= 32768 AC-Link frames)
= 524288 AC-Link frames)
DESCRIPTION
DESCRIPTION
PD Rev 4.5 August 2006
WM9712L
49