Z51F3220FNX Datasheet, PDF (68/312 Pages) Zilog, Inc. – Z8051 Series 8-Bit Microcontrollers

Z51F3220
Product Specification
9.3 P0 Port
9.3.1 P0 Port Description
P0 is 8-bit I/O port. P0 control registers consist of P0 data register (P0), P0 direction register (P0IO), debounce
enable register (P0DB), P0 pull-up resistor selection register (P0PU), and P0 open-drain selection register
(P0OD). Refer to the port function selection registers for the P0 function selection.
9.3.2 Register description for P0
P0 (P0 Data Register) : 80H
7
6
5
4
3
2
1
0
P07
P06
P05
P04
P03
P02
P01
P00
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value : 00H
P0[7:0]
I/O Data
P0IO (P0 Direction Register) : A1H
7
6
5
P07IO
P06IO
P05IO
R/W
R/W
R/W
P0IO[7:0]
4
P04IO
R/W
3
P03IO
R/W
2
P02IO
R/W
1
P01IO
R/W
0
P00IO
R/W
Initial value : 00H
P0 Data I/O Direction.
0
Input
1
Output
NOTE: EC3/EINT0 ~ EINT5 function possible when input
P0PU (P0 Pull-up Resistor Selection Register) : ACH
7
6
5
4
P07PU
P06PU
P05PU
P04PU
R/W
R/W
R/W
R/W
3
P03PU
R/W
2
P02PU
R/W
P0PU[7:0]
Configure Pull-up Resistor of P0 Port
0
Disable
1
Enable
1
P01PU
R/W
0
P00PU
R/W
Initial value : 00H
P0OD (P0 Open-drain Selection Register) : 91H
7
6
5
4
P07OD
P06OD
P05OD
P04OD
R/W
R/W
R/W
R/W
3
P03OD
R/W
2
P02OD
R/W
P0OD[7:0]
Configure Open-drain of P0 Port
0
Push-pull output
1
Open-drain output
1
P01OD
R/W
0
P00OD
R/W
Initial value : 00H
PS029902-0212
PRELIMINARY
65