SAA7282 Datasheet, PDF (9/25 Pages) NXP Semiconductors – Terrestrial Digital Sound Decoder TDSD2

Philips Semiconductors
Terrestrial Digital Sound Decoder (TDSD2)
Product specification
SAA7282
Slave Transmitter
The slave transmitter formats are illustrated thus:
• S SLAVE_ADDR.1 A STATUS_BYTE NA P
In this format the bus master reads the STATUS_BYTE once.
• S SLAVE_ADDR.1 A STATUS_BYTE A ERROR_BYTE NA P
In this format the bus master reads two bytes of STATUS_BYTE and ERROR_BYTE.
• S SLAVE_ADDR.1 A STATUS_BYTE A ERROR_BYTE A AD_BYTE_0 A AD_BYTE_1 NA P
In this format the bus master reads four bytes of STATUS_BYTE, ERROR BYTE and two additional bytes, AD_BYTE_0
and AD_BYTE_1. The additional data bytes contain the eleven additional data bits AD0 to AD10 together with
information regarding their status.
Where NA = no acknowledge.
Table 5 Data byte formats.
BYTE
STATUS_BYTE
ERROR_BYTE
AD_BYTE_0
AD_BYTE_1
D7
D6
PONRES S/M
E7
E6
AD7
AD6
OVW
SAD
D5
D/S
E5
AD5
0
D4
VDSP
E4
AD4
CI2
D3
RSSF
E3
AD3
CI1
D2
OS
E2
AD2
AD10
D1
AM
E1
AD1
AD9
D0
CFC
E0
AD0
AD8
The bits may be defined as follows:
PONRES
This bit is a power-on reset detection bit. It is set HIGH
after a power-on reset or supply reduction and is cleared
LOW when the STATUS_BYTE is read.
S/M (stereo/mono indication)
S/M = logic 1 indicating an incoming stereo transmission.
S/M = logic 0 indicating that the incoming transmission is
not stereo.
D/S (dual/single mono indication)
D/S = logic 1 indicating an incoming dual mono
transmission.
D/S = logic 0 indicating that the incoming transmission is
not dual mono.
VDSP
This bit indicates that the decoded signal is valid digital
sound. When VDSP = logic 0 the incoming transmission
carries either a 704 kbit/s transparent data channel or a
currently undefined format and the device automatically
switches to FM regardless of RSSF.
RSSF
RSSF is the reserve sound switching flag indication equal
to the C4 bit in the NICAM transmission. RSSF = logic 1
when the FM sound signal is carrying the same
programme material as the digitally modulated carrier
(specifically the M1 signal in the event of a dual mono
transmission). RSSF = logic 0 when the FM signal is not
reproduced within the digital signal.
OS
This bit provides an active LOW indication that the decoder
is out of sync. If OS = logic 1 the decoder is frame
synchronized and has obtained C0 (16 frame) sync.
If OS = logic 0, the decoder is out of sync and the indicator
bits are as given in Table 6.
AM
This bit indicates when the automuting function has
switched from the NICAM sound to the conventional FM
sound. This enables the software controller to display the
relevant information to the customer, for example, on
screen display. If AM bit = logic 0 no switching has been
carried out by the automuting function. If AM bit = logic 1
then the automuting function has switched to the FM
inputs.
July 1993
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