wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 58

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

WM9714L
THERMAL SENSOR
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When not in use OUT3 and OUT4 can be powered down using the Powerdown register bits OUT3
and OUT4 (register 3Eh, bits [11:12]). To minimise pops and clicks when the PGA is powered down /
up it is recommended that the Vmid input is selected during the power down / up cycle. This ensures
the same DC level is maintained on the output pin throughout.
Table 39 OUT3 / OUT4 PGA Control
The speaker and headphone outputs can drive very large currents. To protect the WM9714L from
becoming too hot, a thermal sensor has been built in. If the chip temperature reaches approximately
150°C, and the TI bit is set, the WM9714L deasserts GPIO bit 11 in register 54h, a virtual GPIO that
can be set up to generate an interrupt to the CPU (see “GPIO and Interrupt Control” section).
Table 40 Thermal Cutout Control
06h
Speaker
Volume
3Ch
54h
REGISTER
ADDRESS
REGISTER
ADDRESS
13
11
BIT
15
14
13:8
7
6
5:0
BIT
TSHUT
TI
LABEL
MU4
ZC4
OUT4VOL
MU3
ZC3
OUT3VOL
LABEL
1
0
DEFAULT
1 (Mute)
0
000000
(0dB)
1 (Mute)
0
000000
(0dB)
DEFAULT
Thermal Shutdown Disable Control
1 = Disabled
0 = Enabled
Thermal Sensor (virtual GPIO)
1: Temperature below 150°C
0: Temperature above 150°C
See also “GPIO and Interrupt Control” section.
OUT4 Mute Control
1 = Mute
0 = No mute
OUT4 Zero Cross Control
1 = Zero cross enabled (change volume
only on zero crossings, or after time-out)
0 = Zero cross disabled (change volume
immediately)
OUT4 Volume Control
000000 = 0dB (maximum)
… (1.5dB steps)
011111 = -46.5dB
1xxxxx = -46.5dB
OUT3 Mute Control
1 = Mute
0 = No mute
OUT3 Zero Cross Control
1 = Zero cross enabled (change volume
only on zero crossings, or after time-out)
0 = Zero cross disabled (change volume
immediately)
OUT3 Volume Control
000000 = 0dB (maximum)
… (1.5dB steps)
011111 = -46.5dB
1xxxxx = -46.5dB
DESCRIPTION
DESCRIPTION
PP, Rev 3.2, October 2008
Pre-Production
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