Freescale Semiconductor MPC8260 - Manual (Page 611)

MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
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.
Figure 16-1 shows a block diagram of the CMX.