TC1796
System Units (Vol. 1 of 2)
General Purpose I/O Ports and Peripheral I/O Lines
User’s Manual
10-7
V2.0, 2007-07
Ports, V2.0
10.2.1
Port Input/Output Control Registers
The port input/output control registers select the digital output and input driver
functionality and characteristics of a GPIO port pin. Port direction (input or output), pull-
up or pull-down devices for inputs, and push-pull or open-drain functionality for outputs
can be selected by the corresponding bit fields PCx (x = 0-15). Each 32-bit wide port
input/output control register controls four GPIO port lines:
Register Pn_IOCR0 controls the Pn.[3:0] port lines
Register Pn_IOCR4 controls the Pn.[7:4] port lines
Register Pn_IOCR8 controls the Pn.[11:8] port lines
Register Pn_IOCR12 controls the Pn.[15:12] port lines
The diagrams below show the register layouts of the port input/output control registers
with the PCx bit fields. One PCx bit field controls exactly one port line Pn.x.
Pn_IOCR0
Port n Input/Output Control Register 0
(10
H
)
Reset Value: 2020 2020
H
31
28 27
24 23
20 19
16 15
12 11
8 7
4 3
0
PC3
0
PC2
0
PC1
0
PC0
0
rw
r
rw
r
rw
r
rw
r
Field
Bits
Type Description
PC0,
PC1,
PC2,
PC3
[7:4],
[15:12],
[23:20],
[31:28]
rw
Port Control for Port n Pin 0 to 3
This bit field determines the Port n line x functionality
(x = 0-3) according to the coding table (see
0
[3:0],
[11:8],
[19:16],
[27:24]
r
Reserved
Read as 0; should be written with 0.
