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NXP Semiconductors
PNX15xx/952x Series
Volume 1 of 1
Chapter 18: SPDIF Input
PNX15XX_PNX952X_SER_N_4
NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 4.0 — 03 December 2007
18-565
stream is not present or is suddenly removed, and 3) the input signal contains too
much jitter. If the UNLOCK_ENBL bit is set, the SPDIF Input will generate an
interrupt. Note that parity and validity errors (PERR and VERR) do
not cause out of
lock conditions.
From the point where the error condition occurred, the contents of the currently lling
internal 64 byte buffers are muted (zeroed). The external memory buffers will receive
muted data from this point forward. If the receiver does not re-lock before the current
external memory buffer is lled to completion with muted data, DMA will halt. DMA is
halted in this way so that bus resources are not further utilized. Otherwise, DMA
continues with valid data soon after lock is reacquired. From the error point onward,
the last stable capture sample rate will be maintained by the hardware automatically
during this error condition processing. The following is a start-up software process
ow for capture of an SPDIF stream.
3.2.5
SPDI_CTL and Functions
The SPDI_CTL register provides system control of the SPDIF Input interface. The
RESET bit is used to completely reset the interface and all registers. The result of
asserting the RESET bit is all SPDIF Input capture activity stops and all registers are
initialized to logic ‘0’s. In addition, any pending SPDIF Input interrupts are cleared and
disabled. Any pending DMA activity is cancelled and active request are aborted.
Figure 7:
Lock/Unlock Processing for SPDIF Input
Service UNLOCK interrupt
Disable UNLOCK interrupt
Enable LOCK interrupt
Disable capture and/or reset
(optional)
Congure SPDIF Input regis-
ters as necessary.
Enable LOCK interrupt
Disable UNLOCK interrupt
Service LOCK interrupt
Disable LOCK interrupt
Enable UNLOCK interrupt
Enable capture
NO
UNLOCK
indicator auto
asserted by
receiver
Wait a user defined
amount of time -
then increase
oversampling clock
to achieve lock.
YES - LOCK interrupt
generated
LOCK
indicator
active?
UNLOCK
indicator
active?
Normal
audio
processing
YES - UNLOCK
interrupt generated
Power
on/HW
reset/SW
reset