Port Definitions
PRELIMINARY V1.8
79
TABLE 53.
Definition of P1NOPN
14.9.
P3 (Port-3)
The Pin-3.0 to 3.7 have two functional modes, Special output Mode (MODOUT,
TXEN) and Port Mode (Bi-directional Port Mode). Initial Status of PCR3 (Port Control
Register Bit-3) is 0 (low). The PCR3 must be set to high for any case. The direction of
Port-3 can be decided bit-by-bit. The read policy in Port Mode follows that described
before. Read-Modify-Write instructions read the port latch than the pin.
To use Pin-3.0 to 3.7 as a normal input port, PCR3 should be high. If PCR3 is high, the
direction of each Port-3 pin is decided by each P3IO bit. If the P3IO bit-x is high, Port-
3.x is output mode. If low, Port-3.x is input mode. Initial status is input mode because
P3IO (Port-3 I/O Direction Register) is reset to 00000000B. In input mode, pull-up
resistor can be connected by P3RD (Port-3 Resistor Disable Register). If the P3RD bit-x
is high, Port-3.x pull-up resistor is disconnected. If low, Port-3.x pull-up resistor is
connected. Initial status of P3RD is 00000000B, thus pull-up resistor is connected. If
ZCR3 (High-Z Control Register Bit-3) is high, High-Z control is enabled. At this time,
if HIZ bit in the PSCR (Power Saving Control Register) becomes high, pull-up resistor
is disconnected and pin status becomes high impedance. In input mode, P3.0/CPTRU2,
P3.1/CPTRU1, P3.2/CPTRD1, P3.5DI, P3.6/IRQ1, and P3.7/IRQ2 can be used special
input pins.
To use Pin-3.0 to 3.7 as a normal output port, PCR3 should be high. If the P3IO bit-x is
high, Port-3.x is output mode. In output mode, pull-up resistor is not automatically
disconnected regardless P3RD bit-x. If ZCR3 (High-Z Control Register Bit-3) is high,
High-Z control is enabled. At this time, if HIZ bit in the PSCR (Power Saving Control
Register) becomes high, pin status becomes high impedance.
Bit Addr.
None
BIT
7
6
5
4
3
2
1
0
NAME
P1NOPN7 P1NOPN6 P1NOPN5 P1NOPN4 P1NOPN3 P1NOPN2 P1NOPN1 P1NOPN0
Definition
Port-1
Output
Buffer
bit-7
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-6
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-5
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-4
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-3
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-2
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-1
0: CMOS
Push_Pull
1: N-ch
open drain
Port-1
Output
Buffer
bit-0
0: CMOS
Push_Pull
1: N-ch
open drain
Reset Value
0
0
0
0
0
0
0
0
Read/Write
by Software
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Write
by Hardware
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
