
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 18: SPDIF Input
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
18-4
SPDI_SMPMASK.SMASK. The result of the mask operation is zero extended, at
the
least signicant end, to the full 32-bits before being placed in memory. The
resultant 32 bit words are of the form: 0x
nnnnmm00 where the n’s are the 16
msbits of the sample, the
m’s are the masked 8 lsbits subject to SMASK, see
Section 3.2.9. This mode produces audio that is compatible with the PNX2700
Audio Out memory formats.
Raw capture mode: Input subframes are captured and all ‘bi-phase’ encoding
(bits [4:31]) is replaced with a binary representation. The preamble portion (bits
[0:3]) of the subframe is replaced with a code indicating what preamble was
present, see
Figure 3. All parts of the subframe are assembled in order and this
32-bit word is then placed in memory. This mode can be used for “pass-through”
of audio to an external SPDIF OUT block. The external SPDIF OUT block must
be congured appropriately.
2.3.3
SPDIF Input Endian Mode
The SPDIF Input module can store data in memory using either big-endian or little-
endian formatting.
Figure 3:
SPDIF Input: Raw Mode Format
0
31
28
24
20
16
12
8
4
Sample data
L
S
B
M
S
B
B, W or M
pre-amble
Aux.
VU C P
‘bi-phase’ encoded
binary
0
31
28
24
20
16
12
8
4
Sample data
L
S
B
M
S
B
Code
Aux.
VU C P
‘bi-phase’
violations
B preamble replaced with ‘0000’
M preamble replaced with ‘0001’
W preamble replaced with ‘0010’
Input IEC subframe
Output raw mode subframe
Figure 4:
SPDIF Input Sample Order View of Memory
adr
SD.leftn
adr+2
SD.rightn+
adr+4
SD.leftn+1
adr+6
SD.rightn+1
adr+8
SD.leftn+2
adr+10
SD.rightn+2
adr+12
SD.leftn+3
adr+14
SD.rightn+3
16 bit format,
16-bit samples
stereo
32 bit raw mode
format
SubFrame.leftn
adr
SubFrame.rightn
adr+4
SubFrame.leftn+1
adr+8
SubFrame.rightn+1
adr+12
32 bit format,
18-24bit samples
stereo
SD.leftn
adr
SD.rightn
adr+4
SD.leftn+1
adr+8
SD.rightn+1
adr+12