
NT6862-5xxxx
21
12. I/O PORTs
The NT6862 has 25 pins dedicated to input and output.
These pins are grouped into 4 ports.
12.1. PORT0: P00 - P07
PORT0 is an 8-bit bi-directional CMOS I/O port with PMOS
as internal pull-up (Figure 12.1). Each pin of PORT0 may
be bit programmed as an input or output port without
software control the data direction register. When PORT0
works as output, the data to be output are latched to the
port data register and output to the pin. PORT0 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,
then the input signal can be read. This port output is HIGH
after reset.
P00 - P05 are shared with DAC7 - DAC12 respectively. If
ENDK7 - ENDK12
is set
to LOW in ENDAC register, P00 -
P05 will act as DAC7 - DAC12 respectively (Figure 12.2).
After the chip is reset, ENDK7 - ENDK12 will be in the
HIGH state and P00 - P05s will act as I/O ports.
P06
、
P07 are shared with VSYNCO & HSYNCO
respectively. If
ENHOUT
、
ENVOUT
is set
to LOW in
HVCON register, P06
、
P07 will act as VSYNCO &
HSYNCO respectively (Figure 12.3). After the chip is reset,
ENHOUT
&
ENVOUT
will be in the HIGH state and
P06
、
P07 will act as I/O pins.
Addr.
Register
INIT
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
R/W
$0000
PT0
FFH
P07
P06
P05
P04
P03
P02
P01
P00
RW
FFH
-
-
HSYNCI
VSYNCI
HPOLI
VPOLI
HPOLO
VPOLO
R
$0007
HV CON
FFH
ENHOUT
ENVOUT
-
-
-
-
HPOLO
VPOLO
W
$000F
ENDAC
FFH
-
-
ENDK12
ENDK11
ENDK10
ENDK9
ENDK8
ENDK7
W
V
DD
I/O
Data Out
Data In
Figure 12.1. I/O Structure
PWM
Output
PWM
Data In
Figure 12.2. PWM Output Structure
V
DD
O/P
Data Out
Figure 12.3. Output Structure