Nov 01, 2002
page 8 of 136
Notes : Port Pi (i = 0 to 3) has the port Pi direction register which can be used to program each bit for input (“0”) or an output (“1”). The pins programmed as “1” in
the direction register are output pins. When pins are programmed as “0,” they are input pins. When pins are programmed as output pins, the output data are
written into the port latch and then output. When data is read from the output pins, the data of the port latch, not the output pin level, is read. This allows a
previously-output value to be read correctly even if the output LOW voltage has risen due to, for example, a directly-driven light emitting diode was directly
driven. The input pins are in the floating state, so the values of the pins can be read. When data is written into the input pin, it is written only into the port latch,
while the pin remains in the floating state.
❈ LED drive ports 4 (P24–P27)
P50/HSYNC Input P5
Port P5 is a 2-bit input port.
P51/VSYNC Horizonta synchronous signal
The P50 pin is also used as a horizontal synchronous signal input HSYNC for OSD.
Vertical synchronous signal
The P51 pin is also used as a vertical synchronous signal input VSYNC for OSD.
Pins P52–P55 are a 4-bit output port. The output structure is CMOS output.
Pins P52–P55 are also used as OSD output pins R, G, B and OUT respectively. The output
structure is CMOS output.
I/O for data slicer
Input the composite video signal through a capacitor.
Connect a capacitor between VHOLD and Vss.
Connect a filter consisting of a capacitor and a resistor, between HLF and Vss.
Connect a capacitor between FILT and Vss.
Table 7.2 PIN DESCRIPTION (continued)