CS4954-CQ View Datasheet(PDF) - Cirrus Logic
Part Name
Description
Manufacturer
CS4954-CQ Datasheet PDF : 56 Pages
| |||
CS4954 CS4955
which is approximately 3 ppm. Care must be taken
in selecting a suitable clock source.
In MPEG-2 system environments the clock is actu-
ally recovered from the data stream. In these cases
the recovered clock can be 27 MHz ±50 ppm or
±1350 Hz. It varies per television, but in many cas-
es given an MPEG-2 system clock of 27 MHz,
±1350 Hz, the resultant color subcarrier produced
will be outside of the television’s ability to com-
pensate and the chrominance information will not
be displayed (resulting in a black-and-white picture
only).
The CS4954/5 is designed to provide automatic
compensation for an excessively inaccurate
MPEG-2 system clock. Sub-carrier compensation
is enabled through the XTAL bit of the
CONTROL_2 Register. When enabled the
CS4954/5 will utilize a common quartz color burst
crystal (3.579545 MHz ± 50 ppm for NTSC) at-
tached to the XTAL_IN and XTAL_OUT pins to
automatically compare and compensate the color
subcarrier synthesis process.
5.8. Closed Caption Insertion
The CS4954/5 is capable of NTSC Closed Caption
insertion on lines 21 and 284 independently.
Closed captioning is enabled for either one or both
lines via the CC_EN [1:0] Register bits and the
data to be inserted is also written into the four
Closed Caption Data registers. The CS4954/5,
when enabled, automatically generates the seven
cycles of clock run-in (32 times the line rate), start
bit insertion (001), and finally insertion of the two
data bytes per line. Data low at the video outputs
corresponds to 0 IRE and data high corresponds to
50 IRE.
There are two independent 8-bit registers per line
(CC_21_1 & CC_21_2 for line 21 and CC_284_1
& CC_284_2 for line 284). Interrupts are also pro-
vided to simplify the handshake between the driver
software and the device. Typically the host would
write all 4 bytes to be inserted into the registers and
then enable closed caption insertion and interrupts.
As the closed caption interrupts occur the host soft-
ware would respond by writing the next two bytes
to be inserted to the correct control registers and
then clear the interrupt and wait for the next field.
5.9. Programmable H-sync and V-sync
It is possible in master mode to change the H-sync
and V-sync times based on register settings. Pro-
grammable H-sync and V-sync timings are helpful
in several digital video systems, where latencies of
the control signals are present. The user can then
program H-sync and V-sync timing according to
their system requirements. The default values are
244, and 264 for NTSC and PAL respectively.
Address
0×00
0×01
0×04
0×05
0×10
0×11
0×12
0×13
0×14
Register
CONTROL_0
CONTROL_1
CONTROL_4
CONTROL_5
SC_AMP
SC_SYNTH0
SC_SYNTH1
SC_SYNTH2
SC_SYNTH3
NTSC-M NTSC-J
ITU
ITU NTSC-M PAL-
R.BT601 R.BT601 RS170A B,D,G,H,I
01h
01h
21h
41h
12h
10h
16h
30h
07h
07h
07h
07h
78h
78h
78h
78h
1Ch
1Ch
1Ch
15h
3Eh
3Eh
3Eh
96h
F8h
F8h
F8h
15h
E0h
E0h
E0h
13h
43h
43h
43h
54h
PAL-M
61h
12h
07h
78h
15h
C7h
DFh
CDh
43h
Table 4. Multi-standard Format Register Configurations
PAL-N
A1h
30h
07h
78h
15h
96h
15h
13h
54h
PAL-N
Comb.
(Argent)
81h
30h
07h
78h
15h
8Ch
28h
EDh
43h
22
DS278PP4
Share Link: 