Motorola MPC823e - Page 936

Communication Processor Module
16-482 MPC823e REFERENCE MANUAL MOTOROLA
PORTS
COMMUNICATION
16
PROCESSOR MODULE
16.14.4 Port A Example Configurations
The port A pins can be configured in many ways. PA15 can be configured as a
general-purpose I/O pin, but not an open-drain pin. It can also be the USBRXD pin for the
USB. If it is configured as a general-purpose I/O pin, the USBRXD input is internally
grounded. Figure 16-133 and Figure 16-134 illustrate the block diagrams of the PA15 and
PA14 pins.
PA14 can be configured as a general-purpose I/O pin, either open-drain or not. It can also
be the USBOE
pin for the USB. If USBOE is configured as an output on PA14 and the OD14
bit is set in the PAODR, then USBOE
is output from the USB as an open-drain output. If
PA14 is configured as a general-purpose I/O pin, then the USBOE
output is not externally
connected.
Figure 16-133. Parallel Block Diagram For PA15
MUX
MUX
0
1
EN
EN
0
1
USBRXD/PA15
PIN
MUX
EN
1
0
USBRXD
TO
USB
16 BITS
TO
PADAT
BIT 15
OUTPUT
LATCH
PADIR
16 BITS
PAPAR
EN
EN