WM9705_06 WOLFSON [Wolfson Microelectronics plc], WM9705_06 Datasheet - Page 36

• Manufacturer Part Number: WM9705_06
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM9705
REGISTERS 3AH – SPDIF CONTROL REGISTER
VENDOR SPECIFIC REGISTERS (INDEX 5Ah - 7Ah)
w
CONTROL
BIT
PRO
AUDIB
COPY
PRE
CC[6-0]
L
V
back. Sample rate is entered in binary form to the appropriate register. Note sample rates should
only be altered when the relevant DAC or ADC is powered ON.
Register 3Ah is a read/write register that controls SPDIF functionality and manages bit fields
propagated as channel status (or sub-frame in the V case). With the exception of V, this register
should only be written to when the SPDIF transmitter is disabled (SPDIF bit in register 2Ah is ‘0’).
Once the desired values have been written to this register, the contents should be read back to
ensure that the sample rate in particular is supported, then SPDIF validity bit SPCV in register
2Ah should be read to ensure the desired configuration is valid. Only then should the SPDIF
enable bit in register 2Ah be set. This ensures that control and status information start up
correctly at the beginning of SPDIF transmission. WM9705 only supports an SPDIF sample rate
of 48kHz.
Table 20 SPDIF Control Register
These registers are vendor specific. Do not write to these registers unless the Vendor ID register
has been checked first to ensure that the controller knows the source of the AC ‘97 component.
MIXER MUTE PATH (INDEX 5Ah)
Bit 4 (MPM) is used to disable the path between the main input mixer and the lineout mixer, see
Figure 9. Setting this bit to 1, breaks the connection and allows the following combinations:
DAC + PHONE + PCBEEP to line out / headphone out
DAC + CD + LINE + AUX + VID + MIC to mono output
When writing to this register all bits (except MPM) must be written as a 0 or device function can
not be guaranteed. Only the default value can be read from this register.
VENDOR SPECIFIC MODE CONTROL (INDEX 5Ch)
Register 5Ch is a vendor specific control register used to control the function of non-AC’97
specified functions. This register defaults to all special features ‘disabled’ i.e. All zeros.
FUNCTION
Professional; ‘0’ indicates consumer, ‘1’ indicates professional
Non-audio; ‘0’ indicates data is PCM, ‘1’ indicates non-PCM format (eg DD or DTS)
Copyright; ‘0’ indicates copyright is not asserted, ‘1’ indicates copyright
Pre-emphasis; ‘0’ indicates not pre-emphasis, ‘1’ indicates 50/15us pre-emphasis
Category code; programmed as required by user
Generation level; programmed as required by user
Validity bit; ‘0’ indicates frame valid, ‘1’ indicates frame not valid
PD Rev 4.4 August 2006
Production Data
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