Motorola MPC860 PowerQUICC User Manual page 888

Part V. The Communications Processor Module
34.2.2 Port A ConÞguration Examples
This section describes the conÞguration for several PA signals, which are as follows:
¥ PA15 can be conÞgured as a general-purpose I/O signal but not as an open-drain
signal. It can also be RXD1 for SCC1 in NMSI (nonmultiplexed serial interface)
mode. If it is conÞgured as a general-purpose I/O signal, the RXD1 input is
internally grounded. If SCC1 is connected to a TDM or is not used, PA15 can be
used for general-purpose I/O. See Section 34.2.3, ÒPort A Functional Block
Diagrams.Ó
¥ PA14 can be conÞgured as a general-purpose I/O signal, either open-drain or not.
See Section 34.2.3, ÒPort A Functional Block Diagrams.Ó
Ñ If PA14 is conÞgured as a general-purpose I/O signal, the TXD1 output is not
connected externally. If SCC1 is connected to a TDM or is not used, PA14 can
be used for general-purpose I/O.
Ñ In NMSI mode, if TXD1 is an output on PA14 and PAODR[OD14] = 1, TXD1
is an open-drain output from SCC1.
¥ PA11 can be conÞgured as a general-purpose I/O and an open-drain signal. It can
also be the L1TXDB signal for TDMb if PADIR[DR11] is a 1.
¥ PA7 can be conÞgured as a general-purpose I/O signal but not an open-drain signal.
Ñ If PADIR[DR7] = 0, PA7 can also be CLK1, TIN1, L1RCLKA, or all three. The
connections are made separately in the serial interface and timer mode registers.
Ñ If PADIR[DR7] = 1, PA7 can also be BRGO1. If PA7 is a general-purpose I/O
signal, the input to the on-chip peripheral is connected internally to BRG01.
Chapter 21, ÒSerial Interface,Ó describes CLK1 and L1RCLKA.
¥ PA4 can be conÞgured as a general-purpose I/O signal but not an open-drain signal.
Ñ If PADIR[DR4] = 0, PA4 can be CLK4. If DR4 = 1, PA4 can be TOUT2.
Ñ If PA4 is a general-purpose I/O signal, the on-chip CLK4 function is provided
via CLK8 (default input). This is useful because CLK signals cannot always be
routed to all serial channels. See Chapter 21, ÒSerial Interface.Ó
34.2.3 Port A Functional Block Diagrams
Using PA15 as an example, Figure 34-5 shows the functional block diagram for all port A
signals without open-drain capability.
34-6 MPC860 PowerQUICC UserÕs Manual MOTOROLA