GPI/O ports contain alternate functions which
are either output-type or input-type. The GPI/O
illustrated in the following two figures. Note: the
input pin buffer is always enabled.
port
structure
for
each
type
is
GPI/O
GPI/O
Configuration
Register bit-1
(Polarity)
Configuration
Register bit-0
(Input/Output)
SD-bit
nIOW
D-TYPE
GPI/O
Pin
0
1
Transparent
0
1
nIOR
GPI/O
Register
Bit-n
GPI/O
GPIO
Configuration
Register bit-3
(Alt Function)
Configuration
Register bit-2
(Int En)
Alternate
Input
Function
To GP Interrupt
FIGURE 4 - GPI/O HAVING AN INPUT-TYPE ALTERNATE FUNCTION
[GP10, GP11, GP12, GP21]
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