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10/22/14

PI3V724

1 to 2 VGA Demux

Port Selection

When PI3V724 is powered up, MS pin (pin 8) is checked to determine if auto switching is enabled or not. If MS pin is set to low,

PI3V724 will determine if any monitor is attached. If only one monitor is connected, PI3V724 will automatically en¬able the signal

path to the attached monitor. /OUT pin (pin 29) will then be pulled low to indicate the presence of a monitor at the chosen port. If

two monitors are attached to both output ports, PI3V724 will check the Priority pin (pin 30). If Priority pin is set to low, output port

1 will be prioritized and thus active. On the other hand, if Priority pin is high, output port 2 will be prioritized and thus enabled. /

OUT pin will then be pulled low.

Rref External Value Truth Table

Rref

Application Case supported (see page 8 for drawings)

330Kohm Case_150//75

250Kohm Case_75//75

500K

Case_75

Application Scheme

With proper reference resistor assembled to Rref pin (pin 11), monitors with various application schemes can be determined auto-

matically.

Active Blue

Detection Pulse

Active Blue

Back Porch

PI3V724 Vsync Pulse (with Positive Polarity) vs. Blue B2 at 1280x1024@60Hz

14-0168