Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 925

Powerquicc family

Table of Contents

Figure 34-6. Block Diagram for PA14 (True for all Open-Drain Port Signals)

All port B signals can be open-drain. They are configured independently as general-purpose I/O signals if

the corresponding bit in the PBPAR is cleared and they are configured as dedicated on-chip peripheral

signals if the corresponding PBPAR bit is set. When configured as a general-purpose I/O signal, the signal

direction of that signal is determined by the corresponding control bit in the PBDIR. The port I/O signal

is configured as an input if the corresponding PBDIR bit is cleared and it is configured as an output if the

corresponding PBDIR bit is set. All PBPAR bits and PBDIR bits are cleared by hardware reset, thus

configuring all port B signals as general-purpose inputs.

B is shared with the PIP, which is described in

If a port B signal is selected as a general-purpose I/O signal, it can be accessed through the PBDAT where

data is stored in an output latch. If a port B signal is configured as an output, the output latch data is gated

onto the port signal. When PBDAT is read, the port signal itself is read.

All port B signals can have multiple configurations, which include on-chip peripheral functions for

UTOPIA, SPI, I

C, SMCs, and the TDMs. Port B is also multiplexed with the PIP, which can implement

fast parallel interfaces. For a description of the dedicated PIP signal functions, see

Interface Port (PIP)."

Port B provides the PHY address signals for multi-PHY operation and one of the UTOPIA cell-available

control signals. In master mode, PB15 acts as the TxClav input signal; in slave mode (split bus mode

only),PB15 acts as the RxClav output signal.

UTOPIA multi-PHY operations use port B for RxAddr [4:0] and TxAddr [4:0] signals.The number of

active PHY address signals is programmed in UTMODE; for further information see "UTOPIA Mode

Freescale Semiconductor

Chapter 33, "Parallel Interface Port (PIP)."

Chapter 43, "UTOPIA Interface."

MPC885 PowerQUICC Family Reference Manual, Rev. 2

describes port B signal options. Port

Parallel I/O Ports

Chapter 33, "Parallel