wm9704m Wolfson Microelectronics plc, wm9704m Datasheet - Page 32

• Manufacturer Part Number: wm9704m
• Description: Amc97 Audio Modem Codec
• Manufacturer: Wolfson Microelectronics plc

WM9704M
VENDOR RESERVED REGISTERS (INDEX 5AH AND 7AH)
WOLFSON MICROELECTRONICS LTD
The default value after cold or register reset for this register (0000h) defaults to all 0s specifying no
wake-up event. Non-implemented GPIO pins always return 0s.
REGISTER 54H – GPIO PIN STATUS
The GPIO status is a read/write register that reflects the state of all GPIO pins (inputs and outputs)
on slot 12. The value of all GPIO pin inputs and outputs comes in from the codec every frame on slot
12, but is also available for reading as GPIO Pin Status via the standard slot 1 and 2 command
address/data protocols. GPIO inputs configured as Sticky are cleared by writing a 0 to the
corresponding bit of this register 54h.
Bits corresponding to unimplemented GPIO pins should be forced to zero in this register and input
slot 12. GPIO bits that have been programmed as Inputs and Sticky, upon transition either (high-to
low) or (low-to-high) depending on pin polarity, will cause the individual GPIO bit to go asserted 1,
and remain asserted until a write of 0 to that bit. The normal way to set the desired value of a GPIO
output pin is to set the control bit in output slot 12.
The default value, if configured as an input, after cold or register reset for this register is always the
state of the GPIO pin.
REGISTER 56H – MISCELLANEOUS MODEM AFE STATUS/CONTROL
This read/write register defines the loopback modes available for the modem line and handset
ADCs/DACs described in the Intel Specification. Line1 ADC loopback mode 001 L1B0 is supported.
These registers are vendor specific. Do not write to these registers unless the Vendor ID register has
been checked first to ensure that the driver knows the source of the AC‘97 component. Values stored
in this register are used to provide vendor specific modes for the manufacturer.
Table 20 Vendor Register 5Ah Bit Allocation and Default States
Vendor specific Gain control registers – (Index 70h to 74h). The function is as per the other mixer
PGAs. However, the default value of the register changes depending upon the MODE the device is
operating in, as shown in Table 21.
Test only bits – not normal use
User bits
BIT
TRM
DDS
AND
DLM
ADS
AEV
RTS
DFT
DTS
ATS
R2S
HIM
AFT
HIC
BB
I
2
S
NAME
ADC evaluation
BIASBOOST
TSTRECMUX
HALFICONV
MALFIMIX
Dither disable
RAM test mode
DAC FIT test
ADC FIR test
DAC test
ADC test
ADC no DAC
Rev 2.1 switch
I
Dual line modem
Automute disable
2
S enable
DEFAULT
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ACTION WHEN SET TO 1
ADC evaluation mode select bit – do not use
Increases analogue bias currents by 50%
Enables record mux test mode; RECMUX outputs
summed into the front and rear DAC output path.
Halves to bias current to the converters
Halves bias current to the mixer block
Disables ADC and DAC digital dither – do not use
Digital test mode – do not use
Digital test mode – do not use
Digital test mode – do not use
Digital test mode – do not use
Digital test mode – do not use
Select stereo mix into ADC as having no DAC
signal
Closes Rev 2.1 switch when set (see fig 1)
Enables I
43,44,48
Selects support for Line2 DAC and ADC slots
Disables automute function on the front and rear
DACs
2
S data and clock onto GPIO pins
PD Rev 3.2 January 2001
Production Data
32