IDT CONFIDENTIAL
34
V 0.987 11/09
2009 INTEGRATED DEVICE TECHNOLOGY, INC.
92HD81
SINGLE CHIP PC AUDIO SYSTEM, CODEC+SPEAKER AMPLIFIER+CAPLESS HP+LDO
The BTL amplifier includes thermal management circuitry. When the CODEC reaches a temperature
of about 135 degrees, the output amplitude of the BTL amp is gradually lowered until the tempera-
ture falls below 135.
Maximum gain for the BTL amplifier is programmable. The following 4 gain settings relative to a
nominal line output are desired: +6.5dB, +9.5dB, +14.5dB and +16.5dB. Absolute gain may vary and
the suggested accuracy is +/-1.5dB. The gain is exposed in a vendor specific widget and is intended
to mimic the pin programmable gain implemented in discrete BTL amplifiers commonly used in note-
book computers.
2.19. GPIO
2.19.1. GPIO Pin mapping and shared functions
2.19.2. SPDIF/Digital Microphone/GPIO Selection
3 functions are available on the DMIC_1/GPIO0/SPDIFOUT1 pin (pin 46). To determine which func-
tion is enabled, the order of precedence is followed:
1. If the GPIOs are enabled, they override both SPDIF_OUT and Digital Mics
2. If the GPIOs are not enabled through the AFG, then at reset, the pin is pulled low by an internal
pull-down resistor.
3. If the port is enabled as an input, the digital microphones will be used.
4. If the port is enabled as an output, the SPDIF output will be used.
5. In the event that the port is enabled as an input and an output, the port will be an output and the
Digital Mic path will be mute.
2.19.3. Digital Microphone/GPIO Selection
2 functions are available on the DMIC_CLK/GPIO1 (pin 2) and the DMIC_0/GPIO2 (pin 4) pins. To
determine which function is enabled, the order of precedence is followed:
1. If GPIOs are not enabled through the AFG, then at reset, pins 2 and 4 are pulled low by an inter-
nal pull-down resistor.
2. If the GPIO 1 is enabled, the 2 DMIC pins become mute (unless programmed for GPIO or SPDIF
use) and pin 2 becomes an internal pull-down.If GPIO2 is enabled through the AFG, pin 4
becomes a GPIO and is pulled low by an internal pull-down resistor.
3. If the port is enabled as an input, the digital microphones will be used.
4. If the port is not enabled as an input or if the pin is configured as a GPIO, the digital microphone
path will be mute.
GPIO
#
Pin
Supply SPDIF
In
SPDIF
Out
GPI/O
GPI
GP
O
VrefOut
DMIC
VOL
Pull
Up
Pull
Down
0
46
DVDD
YES
IN
50K
1
2
DVDD
YES
CLK
50K
2
4
DVDD
YES
IN
50K