Rev. 1.0, 02/00, page 770 of 1141
27.2.4
Horizontal Sync Signal Threshold Register (HVTHR)
0
0
0
0
0
0
1
1
7
W
HVTH0
1
—
—
6
—
—
5
—
—
4
W
HVTH4
3
W
HVTH3
2
W
HVTH2
1
W
HVTH1
Bit :
Initial value :
R/W :
The HVTHR is a 5-bit write-only register for specifying the threshold value for the digital H
separation counter; this value is used to generate the SEPH signal from the Csync signal. The
SEPH signal is set to 1 when the digital H separation counter value matches the HVTHR value
while the Csync is high, and is reset to 0 when the digital H separation counter value becomes 00
while the Csync is low. When reset, the HVTHR is initialized to H'E0.
Figures 27.3 and 27.4 show the HVTHR value and the SEPH signal generation timing.
Csync
HVTH
SEPH
Digital H separation
counter
About
1.6
µ
s to 2.0
µ
s
Figure 27.3 HVTHR Value and SEPH Generation Timing
When Equalizing Pulses Are Detected