NT68F62 Datasheet, PDF (24/57 Pages) List of Unclassifed Manufacturers – 8-Bit Microcontroller for Monitor (32K Flash MTP Type)

NT68F62
12.5. PORT4: P40 - P41
PORT4 is available only on the 42pin SDIP IC. PORT40 - PORt41 is a 2-bit bi-directional CMOS I/O port with PMOS internal
pull-up (Figure 12.1). Each bi-directional I/O pin may be bit programmed as an input or output port without software
controlling the data direction register. When Port4 works as an output port, the data to be output is latched to the port data
register and output to the pin. Port4 pins that have '1's written to them are pulled high by the internal PMOS pull-ups. In this
state they can be used as input pins. The input signal can be read. This port outputs HIGH after reset.
Addr. Register
INIT
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
R/W
$0005
PT4
FFH
―
―
―
―
―
―
P41
P40
RW
13. H/V Sync Signals Processor
The functions of the sync processor include polarity detection, Hsync & Vsync signals counting, and programmable sync
signals output. It also provides 3-sets of free running signals and special outputs of the test pattern during the burn-in
process when activating the free running output function. The NT68F62 can properly handle either composite or separate
sync signal inputs even without sync signal input. As to processing the composite sync signal, a hardware separator will be
activated to extract the HSYNC signal under the users control. The input at HSYNCI can be either a pure horizontal sync
signal or a composite sync signal. For the sync waveform refer to Figure 13.1 & Figure 13.2.
The sync processor block diagram is shown in Figure 13.3. Both VSYNCI & HSYNCI pins have Schmitt Triggers and filtering
processes to improve noise immunity. Any pulse that is shorter than 125 ns, will be regarded as a glitch and will be ignored.
(a) Positive polarity
(b) Negative polarity
Figure 13.1. Separate H Sync. Waveform
(a) Positive Polarity
(b) Negative Polarity
Figure 13.2. Composite H Sync. Waveform
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