4-9
4. Preset Signal Timing Sheet
Preset
No.
1 2
Item
Abbreviation
VGA 720 x 400 70Hz
VGA 640 x 480 60Hz
Pixel frequency
fc
28.322MHz
25.175MHz
Horizontal frequency
fh 31.47kHz 31.47kHz
Line time total
Th
31.78
µ
s
900CLK
31.78
µ
s
800CLK
Horizontal active display
Thd
25.42
µ
s
720CLK
25.42
µ
s
640CLK
Horizontal sync pulse
Thp
3.81
µ
s
108CLK
3.81
µ
s
96CLK
Horizontal back porch
Thb
1.91
µ
s
54CLK
1.91
µ
s
48CLK
Horizontal front porch
Thf
0.64
µ
s
18CLK
0.64
µ
s
16CLK
Horizontal sync polarity
NEG
POS/NEG
Vertical Frequency
fv
70.09Hz
59.94Hz
Frame time total
Tv
14.27ms
449H
16.68ms
525H
Vertical active display
Tvd
12.71ms
400H
15.25ms
480H
Vertical sync pulse
Tvp
0.06ms
2H
0.06ms
2H
Vertical back porch
Tvb
1.11ms 35H 1.02ms
33H
Vertical front porch
Tvf 0.38ms
12H 0.35ms 10H
Vertical sync polarity
POG
POS/NEG
Full scan mode
Expansion
Expansion
Preset
No.
3 4
Item
Abbreviation
MAC 640 x 480 66Hz
VESA 640 x 480 72Hz
Pixel frequency
fc
30.240MHz
31.500MHz
Horizontal frequency
fh 35.00kHz 37.86kHz
Line time total
Th
28.57
µ
s
864CLK
26.41
µ
s
832CLK
Horizontal active display
Thd
20.43
µ
s
640CLK
20.32
µ
s
640CLK
Horizontal sync pulse
Thp
2.04
µ
s
64CLK
1.27
µ
s
40CLK
Horizontal back porch
Thb
3.17
µ
s
96CLK
4.06
µ
s
128CLK
Horizontal front porch
Thf
2.12
µ
s
64CLK
0.76
µ
s
24CLK
Horizontal sync polarity
POS/NEG
POS/NEG
Vertical Frequency
fv
66.67Hz
72.81Hz
Frame time total
Tv
15.00ms
525H
13.73ms
520H
Vertical active display
Tvd
13.71ms
480H
12.68ms
480H
Vertical sync pulse
Tvp
0.09ms
3H
0.08ms
3H
Vertical back porch
Tvb
1.11ms 39H 0.34ms
28H
Vertical front porch
Tvf 0.09ms 3H 0.24ms
9H
Vertical sync polarity
POG/NEG
POS/NEG
Full scan mode
Expansion
Expansion