NT6868A Datasheet, PDF (6/14 Pages) List of Unclassifed Manufacturers – Keyboard Controller

NT6868A
I/O Ports
The NT6868A has 31 pins dedicated to input and output. These pins are grouped into 6 ports, as follows:
PORT 0 (P00 - P07):
Port 0 is an 8-bit bi-directional CMOS I/O port that is internally pulled High by PMOS. Each pin of port 0 can be bit
programmed as an input or output pin under the software control. When programmed as output, data is latched to the port
data register and output to the pin. Port 0 pins with ''1'' written to them are pulled high by the internal PMOS pull-ups, and
are used as inputs in that state. These input signals can then be read. The port output is High after reset.
PORT 1 ( P10 - P17 ) : Functions the same as PORT 0.
PORT 2 ( P20 - P27) : Functions the same as PORT 0.
PORT 3 ( P30 - P34) : Functions the same as PORT 0.
CLK & DATA
: These two pins have the same structure as I/O ports, except for the 10KΩ internal pull-ups.
PORT Registers:
Addr.
$00C3
$00C4
$00C5
$00C6
$00C7
$00C8
Bit
PORT0
PORT1
PORT2
PORT3
CLK
DATA
7
PD07
PD17
PD27
-
-
-
6
PD06
PD16
PD26
-
-
-
5
PD05
PD15
PD25
-
-
-
4
PD04
PD14
PD24
PD34
-
-
3
PD03
PD13
PD23
PD33
-
-
2
PD02
PD12
PD22
PD32
-
-
1
PD01
PD11
PD21
PD31
-
-
0
PD00
PD10
PD20
PD30
CLK
DATA
(RW)
(RW)
(RW)
(RW)
(RW)
(RW)
WREN
DB
RST
Latch
L
Q
D _SD
VDD
Weak PMOS
IO
RDENB
IO Port Structure
6