
M37221M4H/M6H/M8H/MAH–XXXSP/FP M37221EASP/FP
Rev.1.00 Oct 01, 2002 page 59 of 110
REJ03B0134-0100Z
The vertical display start position is determined by counting the hori-
zontal sync signal (HSYNC). At this time, when VSYNC and HSYNC are
positive polarity (negative polarity), the count starts at the rising edge
(falling edge) of HSYNC signal after the fixed cycle of the rising edge
(falling edge) of VSYNC signal. So the interval from the rising edge
(falling edge) of VSYNC signal to the rising edge (falling edge) of HSYNC
signal needs enough time (2 machine cycles or more) to avoid jitters.
The polarity of HSYNC and VSYNC signals can be select with the OSD
port control register (address 00EC16).
Fig. 8.11.5 Supplement Explanation for Display Position
W
h
e
n
b
i
t
s
0
a
n
d
1
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)
V
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N
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1
2
5
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o
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2
5
[
µ
s
]
(
a
t
f
(
X
I
N
)
=
8
M
H
z
)
Period of counting
H
SYNC
signal
(See note 2)
H
SYNC
si
nal in
ut
Not count
12345
N
o
t
e
s
1
: T
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v
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t
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c
a
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d
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m
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t
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g
f
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n
g
e
d
g
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o
f
H
S
Y
N
C
s
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n
a
l
a
f
t
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r
r
i
s
i
n
g
e
d
g
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V
S
Y
N
C
c
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t
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o
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s
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n
a
l
i
n
t
h
e
m
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c
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c
o
m
p
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.
2
: D
o
n
o
t
g
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n
e
r
a
t
e
f
a
l
l
i
n
g
e
d
g
e
o
f
H
S
Y
N
C
s
i
g
n
a
l
n
e
a
r
r
i
s
i
n
g
e
d
g
e
o
f
V
S
Y
N
C
c
o
n
t
r
o
l
s
i
g
n
a
l
i
n
m
i
c
r
o
c
o
m
p
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t
o
a
v
o
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d
j
i
t
t
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r
.
3
: T
h
e
p
u
l
s
e
w
i
d
t
h
o
f
V
S
Y
N
C
a
n
d
H
S
Y
N
C
n
e
e
d
s
8
m
a
c
h
i
n
e
c
y
c
l
e
s
o
r
m
o
r
e
.
8
m
a
c
h
i
n
e
c
y
c
l
e
s
o
r
m
o
r
e
8 machine cycles
or more
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