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ViewSonic Corporation
Confidential - Do Not Copy
26
17 P3.5/T1 I/O SDA line of I2C communication with EEPROM
18 P3.6/WR I DVI cable detection standard 8052.
19 P3.7/RD O
EEPROM write protection control for DVI EDID Prevent E2PROM
Write instandard 8052.
20 XTAL2 Crystal 22.1184MHz In
21 XTAL1 Crystal 22.1184MHz out
22 GND Sink voltage ground
23 P4.0 A bi-directional I/O port with alternate function.
24 P2.0/A8 DC power on/off control
26 P2.2/A10 OSD
t
control to adjust value to decrease
27 P2.3/A11 Selection of menu command listed
28 P2.4/A12 OSD page selection
29 P2.5/A13 Auto adjustment control
30 P2.6/A14 A bi-directional I/O port with internal pull-ups
31 P2.7/A15 A bi-directional I/O port with internal pull-ups
32 PSEN Program Store Enable
33 ALE Address Latch Enable
34 P4.1 A bi-directional I/O port with alternate function
35 EA I
External Access Enableexternal ROM. The ROM address and data
will not be presented on the bus ifthe EA pin is high and the
program counter is within the 64 KB area.
36 P0.7/AD7 I/O DDR Direct Bus Communication with Scaler
37 P0.6/AD6 I/O DDR Direct Bus Communication with Scaler
38 P0.5/AD5 I/O DDR Direct Bus Communication with Scaler
39 P0.4/AD4 I/O DDR Direct Bus Communication with Scaler
40 P0.3/AD3 I/O WRZ line of DDR Direct Bus
41 P0.2/AD2 I/O RDZ line of DDR Direct Bus
42 P0.1/AD1 I/O ALE line of DDR Direct Bus
43 P0.0/AD0 O Hardware reset to Scaler
44 +5V I +5V for MCU working voltage
VA702-2_VA721-3_VA721b-3
25 P2.1/A9 OSD
u
control to adjust value to increase