MPC8280 datasheet(613/1386 Pages) FREESCALE

613 / 1386 page

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

16-1

Chapter 16

CPM Multiplexing

The CPM multiplexing logic (CMX) connects the physical layer—UTOPIA, MII, modem lines, TDM

lines and proprietary serial lines to the FCCs, SCCs and SMCs. The CMX features the following two

modes:

•

In NMSI mode, the CMX allows all serial devices to be connected to their own set of individual

pins. Each serial device that connects to the external world in this way is said to connect to a

nonmultiplexed serial interface (NMSI). In the NMSI configuration, the CMX provides a flexible

clocking assignment for each FCC, SCC and SMC from a bank of external clock pins and/or

internal BRGs.

•

In TDM mode, the CMX performs the connection of the serial devices to the SIs for using the

time-slot assigner (TSA). This allows any combination of MCCs, FCCs, SCCs, and SMCs to

multiplex data on any of the eight TDM channels. The CMX connects the serial device only to the

TSA in the SIx. The actual multiplexing of the TDM is made by programming the SIx RAM. In

TDM mode, all other pins used in NMSI mode are available for other purposes. See Chapter 15,

“Serial Interface with Time-Slot Assigner.”

The CMX also allows the user to route the multiple-PHY address to FCC1 or to FCC2 in various

combinations, allowing the use of both FCCs in multiple-PHY mode.

NOTE

The CMX serves both SI1 and SI2. When the user programs the CMX to

connect a serial device to the SI, the CMX connects that serial device to both

SIs. Programming both SIs to use one serial device in the same time slot

causes erratic behavior.

MPC8280 Datasheet(PDF) 613 Page - Freescale Semiconductor, Inc