wm8580a Wolfson Microelectronics plc, wm8580a Datasheet - Page 65

• Manufacturer Part Number: wm8580a
• Description: Multichannel Codec With S/pdif Transceiver
• Manufacturer: Wolfson Microelectronics plc

Production Data
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Table 61 S/PDIF Receiver Input Selection Register
REGISTER
SPDMODE
ADDRESS
PWRDN 2
GPO2
GPO3
R36
R39
R40
R51
24h
27h
28h
33h
AUDIO DATA HANDLING
The S/PDIF receiver recovers the data and VUCP bits from each sub-frame. If the S/PDIF input data
is in a non-compressed audio format the data can be internally routed to the stereo data input of
DAC1. The WM8580 can detect when the data is in a non-compressed audio format and will
automatically mute the DAC. See Non-Audio Detection section for more detail.
The received data can also be output over the digital audio interfaces in any of the data formats
supported. This can be performed while simultaneously using DAC1 for playback. The received data
may also be re-transmitted via the S/PDIF transmitter.
USER DATA
The WM8580 can output recovered user data received using GPO pins. See Table 72 for General
Purpose Pin control information.
CHANNEL STATUS DATA
The channel status bits are recovered from the incoming data stream and are used to control various
functions of the device.
The S/PDIFRx interface always receives 24 bits of data in bits 4 to 27 of the SPDIF payload. The
audio sample can be either 20 bits if AUX bits not used or up to 24bits if AUX bits used (refer to
Figure 39). So the audio sample can be 20,21,22,23 or 24 bit. The source (wherever the S/PDIF data
is coming from) of the S/PDIF data stream must set the MAXWL and RXWL within the status bits to
indicate the size of the audio sample. This is then recovered by the S/PDIF Rx interface. The S/PDIF
Rx interface ALWAYS receives 24 bits, but if the actual length of the audio data sample (indicated by
MAXWL and RXWL) is less than 24 bits, then the user has the option to truncate these 24 bits to the
actual size. These truncated bits are then sent to either the SPDIF Tx or the AIF. Truncation may
allow users to process data faster. If the user does not want this truncation to happen then they must
mask the truncation using the WL_MASK. In this case all 24 bits of data received are transferred.
BIT
2:1
3:0
7:4
3:0
5
0
6
SPDIFIN1MODE
RXINSEL[1:0]
WL_MASK
GPO3OP[3:0]
GPO4OP[3:0]
GPO5OP[3:0]
SPDIFRXD
LABEL
DEFAULT
0010
0011
0100
00
1
1
0
Selects the input circuit type for the SPDIFIN1 input
0 = CMOS-compatible input
1 = Comparator input. Compatible with 500mVpp AC
coupled consumer S/PDIF input signals as defined in
IEC60958-3.
S/PDIF Receiver input mux select.
The general purpose inputs must be configured using
GPOxOP to be either CMOS or comparator inputs if
selected by RXINSEL.
00 = Select SPDIFIN1
01 = Select SPDIFIN2 (MFP3)
10 = Select SPDIFIN3 (MFP4)
11 = Select SPDIFIN4 (MFP5)
S/PDIF Receiver Word Length Truncation Mask
0 = disabled, data word is truncated as described in
Table 66.
1 = enabled, data word is not truncated.
GPO pin Configuration Select.
1110 = Set GPO as S/PDIF input (CMOS-compatible
input).
1111 = Set GPO as S/PDIF input (compatible with
500mVpp AC coupled consumer S/PDIF input signals
as defined in IEC-60958-3).
For GPO defaults, see Table 72.
S/PDIF Receiver powerdown.
0 = S/PDIF Receiver enabled
1 = S/PDIF Receiver disabled
DESCRIPTION
PD, Rev 4.7, March 2009
WM8580
65