wm8580a Wolfson Microelectronics plc, wm8580a Datasheet - Page 71

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

Production Data
Table 71 S/PDIF Receiver Automatic Error Handling Configuration Registers
w
REGISTER
ADDRESS
GP01
GP02
27h
R38
R39
26h
BIT
8
8
ERROR HANDLING IN SOFTWARE MODE
When the TRANS_ERR flag is asserted, it indicates that the recovered Rx S/PDIF sub-frame
is corrupted. This corruption can due to a BI-Phase error, a parity error or a pre-amble
error.When the INVALID flag is asserted, it indicates that the recovered Rx S/PDIF sub-frame
has been marked as being invalid by the source of the S/PDIF data. Both TRANS_ERR and
INVALID indicate an error.
The S/PDIF receiver has two modes of handling for these errors, manual and automatic. The
mechanism for each flag is similar. The mechanisms are described below.
MANUAL ERROR HANDLING
This manual handling of errored Rx S/PDIF data can be used when an application processor
is being interrupted via the INT_N signal. Appropriate action should be taken by the
application processor to handle the error condition
If the TRANS_ERR and INVALID error flags are not masked using the MASK register, the
recovered S/PDIF Rx data is passed to the digital audio interface and DAC1 or to the S/PDIF
transmitter irrespective of the state of the flag and the data content of the recovered
stream.(Also refer to note 1 below). In this case, the application processor will be interrupted
via the INT_N signal.
AUTOMATIC ERROR HANDLING
This automatic handling of errored Rx S/PDIF data can be used when an application
processor is not being interrupted via the INT_N signal leaving the WM8580 to handle the
error condition.
If the TRANS_ERR and INVALID error flags are masked using the MASK register, the
WM8580 output data from the S/PDIF Rx interface depends on the setting of FILLMODE. If
FILLMODE=1, then the incoming data (which is errored) is overwritten with 0’s. If
FILLMODE=0, then the last valid data sample is repeatedly output.
For the INVALID flag, the automatic error handling can be disabled if ALWAYSVALID =1. If
ALWAYSVALID is set, then the recovered Rx S/PDIF data, which is marked as invalid, will be
allowed to pass to the digital audio interface or to the S/PDIF transmitter. The data will not be
modified in any way.
Notes
1.
ALWAYSVALID
For the S/PDIF receiver to S/PDIF transmitter data path, only the INVALID flag will
cause data to be overwritten, the TRANS_ERR flag is not used to overwrite data which
is passed to the S/PDIF transmitter.
FILLMODE
LABEL
DEFAULT
0
0
Fill Mode Overwrite Configuration
Determines S/PDIF receiver action when TRANS_ERR or
INVALID flag is masked and error condition sets the flag:
0 = Data from S/PDIF receiver is overwritten with last valid
data sample when flag is set.
1 = Data from S/PDIF receiver is overwritten as all zeros
when flag is set.
Automatic Error Handling Configuration for INVALID
Flag
0 = INVALID flag automatic error handling enabled.
1 = INVALID flag automatic error handling disabled.
DESCRIPTION
PD, Rev 4.7, March 2009
WM8580
71