SM5956A NPC, SM5956A Datasheet - Page 18

• Manufacturer Part Number: SM5956A
• Description: 6-channel Asynchronous Sample Rate Converter
• Manufacturer: NPC

w w w . D a t a S h e e t 4 U . c o m
Validity flag
The validity flag is set to 0 when the audio sample word transferred is valid, and is set to 1 when the data is
invalid. The SM5956A sets the validity flag to 1 when direct mute is turned ON.
User data
The user data are user-defined bits originally provided in the standard in response to user requests, but the
SM5956A sets all user data bits to 0.
Channel status
The channel status bits can be used to transfer various information, including audio sample word length, pre-
emphasis, sampling frequency, time codes, source numbers, and destination codes. The SM5956A sets only 9
bits: CP1, CP2, LBIT, CNTL0 to 3, CFS1, and CFS2. The 15th bit of the 8th to 15th bit in the category code
can be used to set LBIT status bit but 8th to 14th bit were determined by the category codes CATGY0, 1 (See
“Register table”). All other bits are set to 0.
Parity bit
The parity bit is used to indicate when an odd number of errors occur due to interface problems. The SM5956A
sets the parity bit to 1 if the number of 1 bits in the other 27 data bits of the digital audio interface (excluding
the preamble) is odd, and sets the parity bit to 0 if the number of 1 bits is even, thereby insuring that the number
of 1 bits in the 28-bit data is always even.
1164
112
128
144
160
176
12
24
36
16
32
48
64
80
96
0
0
:
CNTL0 CNTL1 CNTL2 CNTL3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
:
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
:
2
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
:
3
0
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
0
:
L = 1
4
0
0
0
0
0
4
0
0
0
0
0
0
0
0
0
0
0
:
R = 1
5
0
0
0
0
0
5
0
0
0
0
0
0
0
0
0
0
0
:
6
0
0
0
0
0
6
0
0
0
0
0
0
0
0
0
0
0
0
:
SM5956A
7
0
0
0
0
0
0
0
0
0
0
0
0
7
0
0
0
0
0
:
CFS1
8
0
0
0
0
0
×
8
0
0
0
0
0
0
0
0
0
0
:
CFS2
9
0
0
0
0
0
×
9
0
0
0
0
0
0
0
0
0
0
:
10
10
0
0
0
0
0
×
0
0
0
0
0
0
0
0
0
0
0
:
SEIKO NPC CORPORATION —18
11
11
×
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
:
CP1
12
×
0
0
0
0
0
0
0
0
0
0
CP2
13
0
0
0
0
0
0
0
0
0
0
0
14
0
0
0
0
0
0
0
0
0
0
0
0
LBIT
15
0
0
0
0
0
0
0
0
0
0
0