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MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

28-1

Chapter 28

Serial Management Controllers (SMCs)

The two serial management controllers (SMCs) are full-duplex ports that can be configured independently

to support one of three protocols or modes—UART, transparent, or general-circuit interface (GCI). Simple

UART operation is used to provide a debug/monitor port in an application, which allows the SCCs to be

free for other purposes. The SMC in UART mode is not as complex as that of the SCC in UART mode.

The SMC clock can be derived from one of the internal baud rate generators or from an external clock

signal. However, the clock should be a 16

× clock.

In totally transparent mode, the SMC can be connected to a TDM channel (such as a T1 line) or directly

to its own set of signals. The receive and transmit clocks are derived from the TDM channel, the internal

baud rate generators, or from an external 1

× clock. The transparent protocol allows the transmitter and

receiver to use the external synchronization signal. The SMC in transparent mode is not as complex as that

of the SCC in transparent mode.

Each SMC supports the C/I and monitor channels of the GCI bus, for which the SMC connects to a

time-division multiplex (TDM) channel in a serial interface (SIx). SMCs support loopback and echo

modes for testing. The SMC receiver and transmitter are double-buffered, corresponding to an effective

FIFO size (latency) of two characters. Chapter 15, “Serial Interface with Time-Slot Assigner,” describes

GCI interface configuration.

Figure 28-1 shows the SMC block diagram.

Figure 28-1. SMC Block Diagram

Shifter

SYNC

Data

RXD

Control

Logic

TXD

Control

Registers

Shifter

Peripheral Bus

CLK

60x Bus

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