SM5902AF Nippon Precision Circuits Inc, SM5902AF Datasheet - Page 31

• Manufacturer Part Number: SM5902AF
• Description: compression and non compression type shock-proof memory controller
• Manufacturer: Nippon Precision Circuits Inc

The digital audio sample data is a 20-bit digitized
audio signal. Auxiliary audio data, on the other
hand, can be audio sample data of varying length.
Digital audio interface
When the DIT flag is set to 1, the digital audio inter-
face output from pin DIT is enabled. The output
Preamble
The preamble is a particular bit pattern used to per-
form subframe and block synchronization and dis-
crimination, assigned to one of 4 time slot divisions
(0 to 3), comprising 8 continuous biphase modulat-
ed transfer rate status indicators.
Digital audio sample data and auxiliary audio
Audio sample validity
The validity flag is set to 0 when the digital audio
sample data is output correctly, or it is set to 1 if the
output is incorrect. It is also set to 1 if encoding
0
M
(Sync Groupe)
The SM5902AF starts with 0, so only the preamble patterns for leading symbol = 0 are used.
Preamble
Channel 1 W
Preamble
W
M
Frame 191
B
3 4
Auxiliary
Channel 2
7 8
Leading symbol = 0
Digital Audio Sample Data
B
Start Block
Figure 6. Subframe format
Sub Frame
11101000
11100010
11100100
Figure 5. Frame format
Channel 1
SM5902AF
Frame 0
Frame 0
Audio Sample Validity
Audio Channel Status
W
data structure is modulated using a preamble and
biphase mark encoding.
There are 3 types of preamble. The leading pream-
ble pattern of all blocks is preamble pattern B,
which is then followed by preamble pattern M for
channel 1, and preamble pattern W for channel 2.
The SM5902AF uses a 16-bit audio data structure
internally with audio data output bits 4 to 11 set to 0
and bits 12 to 27 output in LSB first format.
does not start when the device is operating in
forced mute, microcontroller forced mute, and
shockproof mode.
Channel coding
Sub Frame
Sub Frame Parity
Channel 2
User Bit Data
27 28
Leading symbol = 1
M
V
NIPPON PRECISION CIRCUITS-31
00010111
00011101
00011011
Channel 1
U
Frame 1
C
W
P
31
Channel 2