WM9711 datasheet(37/66 Pages) WOLFSON

37 / 66 page

Production Data

WM9711L

PD Rev 4.1 April 2004

BATTERY ALARM

PRINCIPLE OF OPERATION

The WM9711L 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 CREF (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 WM9711L from sleep mode. COMP1 (pin 29) corresponds to GPIO bit 15

and COMP2 (pin30) to bit 14.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

CP1

COMP1 Polarity (see also “GPIO and Interrupt

Control”)

0: Alarm when COMP1 voltage is above VREF

1: Alarm when COMP1 voltage is below VREF

4Eh

CP2

COMP2 Polarity (see also “GPIO and Interrupt

Control”)

0: Alarm when COMP2 voltage is above VREF

1: Alarm when COMP2 voltage is below VREF

58h

15:13

COMP2

DEL

Low Battery Alarm Delay

000: No delay

001: 0.17s (2

13 = 8192 AC-Link frames)

010: 0.34s (2

14 = 16384 AC-Link frames)

011: 0.68s (2

15 = 32768 AC-Link frames)

100: 1.4s (2

16 = 65536 AC-Link frames)

101: 2.7s (2

17 = 131072 AC-Link frames)

110: 5.5s (2

18 = 262144 AC-Link frames)

111: 10.9s (2

19 = 524288 AC-Link frames)

Table 25 Comparator Control

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

Comparator 1 Reference Voltage

VREF = AVDD/2

C1REF

WIPER/AUX4 (pin 12)

Comparator 1 Signal Source

AVDD/2 when C1REF=’1’. Otherwise

comparator 1 is powered down

COMP1/AUX1 (pin 29)

COMP2/AUX2 (pin 30)

13:12

C1SRC

BMON/AUX3 (pin 31)

Comparator 2 Reference Voltage

VREF = AVDD/2

C2REF

WIPER/AUX4 (pin 12)

Comparator 2 Signal Source

AVDD/2 when C2REF=’1’. Otherwise

comparator 2 is powered down

COMP1/AUX1 (pin 29)

COMP2/AUX2 (pin 30)

5Ch

Additional

Analogue

Functions

10:9

C2SRC

BMON/AUX3 (pin 31)

Table 26 Comparator Reference and Source Control

WM9711 Datasheet(PDF) 37 Page - Wolfson Microelectronics plc

WM9711 Datasheet(HTML) 37 Page - Wolfson Microelectronics plc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

Datasheet Download

Link URL