XC886/888CLM
Parallel Ports
User’s Manual
6-10
V1.3, 2010-02
Parallel Ports, V 1.0
6.1.1.5
Alternate Input and Output Functions
The number of alternate functions that uses a pin for input is not limited. Each port control
logic of an I/O pin provides several input paths of digital input value via register or direct
digital input value.
Alternate functions are selected via an output multiplexer which can select up to four
output lines. This multiplexer can be controlled by the following registers:
•
Register Px_ALTSEL0
•
Register Px_ALTSEL1
Selection of alternate functions is defined in registers Px_ALTSEL0 and Px_ALTSEL1.
Note: Set Px_ALTSEL0.Pn and Px_ALTSEL1.Pn to select only implemented alternate
output functions.
Px_ALTSELn (n = 0 - 1)
Port x Alternate Select Register
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
rw
rw
rw
rw
rw
rw
rw
rw
Field
Bits
Type Description
Pn
(n = 0 - 7)
n
rw
Pin Output Functions
Configuration of Px_ALTSEL0.Pn and
Px_ALTSEL1.Pn for GPIO or alternate settings:
00
Normal GPIO
10
Alternate Select 1
01
Alternate Select 2
11
Alternate Select 3
*