SAA5233 データシートの表示（PDF） - Philips Electronics
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SAA5233 Datasheet PDF : 20 Pages
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Philips Semiconductors
Dual standard PDC decoder
Objective specification
SAA5233
Register 00:Control/Status (reset state XXX0 XX00)
Register 00 is split into two parts. The control part (WRITE only) consisting of bits D4, D1 and D0 and status part (READ
only) consisting of bits D7 to D5.
Table 6 Register 00.
D7
D6
D5
D4
−
−
−
IEL
DSQ
8/30/2 RF
VPS RF
−
D3
D2
D1
D0
−
−
ACQ 8/30/2 ACQ VPS
−
−
−
−
Table 7 Register 00 bit description.
SYMBOL
IEL
ACQ 8/30/2
ACQ VPS
DSQ
8/30/2 RF
VPS RF
BIT
FUNCTION
D4
Interrupt Error Level.
When logic 0, signal only completely valid data lines from Teletext packet 8/30/2
received and VPS received flags.
When logic 1, signal valid framing code and Teletext packet header 8/30/2 received or
valid start codeword for VPS received.
D1
Acquire 8/30/2.
D0
Acquire VPS.
Allows selective decoding of either Teletext packet 8/30/2 data or VPS data. If both are
set to the same value the system automatically selects the format being transmitted
(see Table 8).
D7
Data Signal Quality.
When logic 1, good Teletext or VPS data signal is being received.
When logic 0, no Teletext or VPS data signal is being received.
D6
8/30/2 Received Flag.
When logic 1, and IEL (D4) = logic 0 an error-free Teletext packet 8/30/2 has been
received, Hamming decoded and stored in the RAM. When logic 1, and IEL(D4) =
logic 1 a Teletext packet with a valid framing code and 8/30/2 header has been
received, Hamming decoded and stored in RAM.
When logic 0 no Teletext packet 8/30/2 data received.
D5
VPS Received Flag.
When logic 1, and IEL(D4) = logic 0, an error-free VPS data line has been received,
biphase decoded and stored in the RAM. When logic 1, and IEL(D4) = logic 1 a VPS
data line with valid start code has been received, biphase decoded and stored in RAM.
When logic 0 no VPS data received.
Table 8 Selection of Teletext packet 8/30/2 data or VPS data.
ACQ 8/30/2
0
0
1
1
ACQ VPS
0
1
0
1
FUNCTION
use automatic selection algorithm for line 16
acquire only VPS data on every VBI line
acquire only 8/30/2 data on every line 16
use automatic selection algorithm for line 16
June 1994
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