wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 70

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9714L
w
The WM9714L 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
COMP1 (pin 29) or COMP2 (pin 30), 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 WM9714L from sleep mode. COMP1/AUX1 (pin 29) corresponds to GPIO bit
15 and COMP2/AUX2 (pin30) to bit 14.
Table 53 Comparator Control
Table 54 Comparator Reference and Source Control
4Eh
5Ah
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
000
0
00
0
00
DEFAULT
DEFAULT
COMP1 Polarity Control
0: Alarm when COMP1 voltage is below VREF
1: Alarm when COMP1 voltage is above VREF
Note: see also “GPIO and Interrupt Control”
COMP2 Polarity Control
0: Alarm when COMP2 voltage is below VREF
1: Alarm when COMP2 voltage is above VREF
Note: see also “GPIO and Interrupt Control”
Low Battery Alarm Delay Control
000 = No delay
001 = 2
010 = 2
011 = 2
100 = 2
101 = 2
110 = 2
111 = 2
Comparator 1 Reference Voltage Select
0 = AVDD/2
1 = AUX4 (pin 12)
Comparator 1 Signal Source
00 = AVDD/2 when C1REF=1, else COMP1
powered down
01 = COMP1/AUX1 (pin 29)
10 = COMP2/AUX2 (pin 30)
11 = Reserved
Comparator 2 Reference Voltage Select
0 = AVDD/2
1 = AUX4 (pin 12)
Comparator 2 Signal Source
00 = AVDD/2 when C2REF=1, else COMP2
powered down
01 = COMP1/AUX1 (pin 29)
10 = COMP2/AUX2 (pin 30)
11 = Reserved
13
14
15
16
17
18
19
AC-link frames (0.17s)
AC-link frames (0.34s)
AC-link frames (0.68s)
AC-link frames (1.4s)
AC-link frames (2.7s)
AC-link frames (5.5s)
AC-link frames (10.9s)
DESCRIPTION
DESCRIPTION
PP, Rev 3.2, October 2008
Pre-Production
70