MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
(8) Clock run-in determination circuit
This circuit sets a window in the clock run-in portion in the composite
video signal, and then determinates clock run-in by counting the
number of pulses in this window. Set the time from a falling of the
horizontal synchronizing signal to a start of the window by bits 0 to 5
of the window register (address 00E216; refer to Figure 43). The
window ends according to the contents of the setting of the start bit
position register (refer to Figure 40).
Window Register
b7 b6 b5 b4 b3 b2 b1 b0
0
0
Window register (WN) [Address 00E216
]
R
R
W
W
B
Name
Functions
After reset
0
0
to
5
Window start time
(WN0 to WN5)
Time from a falling of the horizontal
synchronous signal to start of the
window =
4 ✕ set value (“0016” to “3F16”) ✕
reference clock period
6, 7
0
R
W
Fix these bits to “0.”
Fig. 43. Window Register
47
RENESAS [ RENESAS TECHNOLOGY CORP ]
