wm8802scft/v Wolfgang Knap, wm8802scft/v Datasheet - Page 28

• Manufacturer Part Number: wm8802scft/v
• Description: Digital Audio Interface Transceiver
• Manufacturer: Wolfgang Knap

WM8802
w
PLL LOCK ERROR
The PLL becomes unlocked for input data that has lost bi-phase modulation regularity or input data
where preambles B, M, and W cannot be detected.
RERR goes High during the occurrence of a PLL lock error and returns to Low when data
demodulation returns to normal. High is maintained between 45ms and 300ms.
The rising and falling edges of RERR are synchronized with RLRCK.
INPUT DATA PARITY ERROR
Input parity errors are detected if there are an odd number of parity bits in input data.
RERR goes High indicating that the PLL is locked if an input parity error occurs 9 or more times in
succession, It returns to Low after being High for between 45ms and 300ms.
The error flag output format, for when an input parity error is output 8 times in succession, can be
selected using REDER.
OTHER ERRORS
The channel status bits 24 to 27 (sampling frequency) are always read and the data of the previous
block is compared with the current data, even if RERR goes Low. The input data sampling frequency
is also calculated from the fs clock extracted from the input data and fs calculation value comparison
is performed as described above. RERR is instantly made High if a difference is detected, and the
same processing as for PLL lock errors is performed.
The PLL causes a lock error when the sampling frequency changes as described above. FSERR can
be set to support sources with a variable sampling frequency (for example a CD player with a
variable pitch function). No error flag is output if the sampling frequency variation falls within the PLL
capture range while using FSERR.
For input data within the reception range, FSERR prevents fs calculation results from being reflected
in the error flag that is set using FSLIM[0:1]. RERR goes Low if the PLL status changes to the locked
status.
RERR changes to a High output upon detection of non-PCM data input if RESEL is set. The PLL
locked status and various output clocks continue to be output according to the input data but the
output data is muted.
DATA PROCESSING UPON ERROR OCCURRENCE (LOCK ERROR, PARITY
ERROR)
The data processing after the occurrence of an error is described below. If 8 or fewer input parity
errors occur in succession transfer data is replaced by the data saved to L-ch and R-ch in the
previous frame of PCM audio data. The error data is output as it is if the transfer data is non-PCM
data. Non-PCM data is based on data detected prior to occurrence of an input parity error when bit 1
of the channel status goes High.
Output data is muted upon occurrence of a PLL lock error or when a parity error occurs 9 or more
times in succession.
For the channel status, the data of the previous block is held in 1-bit units when a parity error occurs.
PP Rev 1.1 April 2004
Product Preview
28