2002 Nov 22
22
NXP Semiconductors
Preliminary specification
48 kHz IEC 60958 audio DAC
UDA1352TS
11.3.1
F
ORMAT
OF
THE
BITSTREAM
The non-PCM data is transmitted in data bursts, consisting of four 16-bit words (called Pa, Pb, Pc and Pd) followed by
the so called burst-payload. The definition of the burst preambles is given in Table 15.
Table 15
Burst preamble words
11.3.2
B
URST
INFORMATION
The burst information given in preamble Pc, meaning the information contained in the data stream, is defined according
to IEC 60958 as given in Table 16.
Table 16
Fields of burst information in preamble Pc
PREAMBLE WORD
LENGTH OF THE FIELD
CONTENTS
VALUE
Pa
16 bits
sync word 1
F872 (hex)
Pb
16 bits
sync word 2
4E1F (hex)
Pc
16 bits
burst information
see Table 16
Pd
16 bits
length code
number of bits
BITS OF Pc
VALUE
CONTENTS
REFERENCE
POINT R
REPETITION TIME OF
DATA BURST IN
IEC 60958 FRAMES
0 to 4
0
NULL data
−
none
1
AC-3 data
R_AC-3
1536
2
reserved
−
−
3
pause
bit 0 of Pa
refer to IEC 60958
4
MPEG-1 layer 1 data
bit 0 of Pa
384
5
MPEG-1 layer 1, 2 or 3 data or MPEG-2
without extension
bit 0 of Pa
1152
6
MPEG-2 with extension
bit 0 of Pa
1152
7
reserved
−
−
8
MPEG-2, layer 1 low sampling rate
bit 0 of Pa
768
9
MPEG-2, layer 2 or 3 low sampling rate
bit 0 of Pa
2304
10
reserved
−
−
11 to 13
reserved (DTS)
−
refer to IEC 61937
14 to 31
reserved
−
−
5 to 6
0
reserved
−
−
7
0
error flag indicating a valid burst-payload
−
−
1
error flag indicating an invalid
burst-payload
−
−
8 to 12
−
data type dependant information
−
−
13 to 15
0
bitstream number
−
−
