Philips Semiconductors
Preliminary specification
PAL/NTSC/SECAM video decoder with adaptive PAL/NTSC
comb filter, VBI-data slicer and high performance scaler
SAA7114H
9.3
Clock and real-time synchronization signals
The Line-Locked Clock (LLC) is the double pixel clock of
nominal 27 MHz. It is locked to the selected video input,
generating baseband video pixels according to “ITU
recommendation 601”. In order to support interfacing
circuitries, a direct pixel clock LLC2 is also provided.
For the generation of the line-locked video (pixel) clock
LLC, and of the frame locked audio serial bit clock, a
crystal accurate frequency reference is required. An
oscillator is built in, for fundamental or third harmonic
crystals. The supported crystal frequencies are 32.11 or
24.576 MHz (defined during reset by strapping
pin ALRCLK).
The pins for line and field timing reference signals are
RTCO, RTS1 and RTS0. Various real-time status
information can be selected for the RTS pins. The signals
are always available (output) and reflect the
synchronization operation of the decoder part in the
SAA7114H. The function of the RTS1 and RTS0 pins can
be defined by bits RTSE1[3:0]12H[7:4] and
RTSE0[3:0]12H[3:0].
Alternatively pin XTALI can be driven from an external
single ended oscillator.
The crystal oscillation can be propagated as clock to other
ICs in the system via pin XOUT.
Table 25 Clock and real-time synchronization signals
SYMBOL PIN I/O
DESCRIPTION
BIT
Crystal oscillator
XTALI
XTALO
XOUT
7
6
4
I
input for crystal oscillator, or reference clock
output of crystal oscillator
−
−
O
O
reference (crystal) clock output drive (optional)
XTOUTE[14H[3]]
Real-time signals (RT port)
LLC
28
O
line-locked clock, nominal 27 MHz, double pixel clock locked to the
selected video input signal
−
LLC2
29
36
O
O
line-locked pixel clock, nominal 13.5 MHz
−
−
RTCO
real-time control output, transfers real-time status information
supporting RTC level 3.1 (see external document “RTC Functional
Description”, available on request)
RTS0
RTS1
34
35
O
O
real-time status information line 0, can be programmed to carry various RTSE0[3:0]12H[3:0]
real-time informations (see Table 55)
real-time status information line 1, can be programmed to carry various RTSE1[3:0]12H[7:4]
real-time informations (see Table 56)
2000 Mar 15
61
NXP [ NXP ]
