Motorola MPC8260 User Manual

MOTOROLA

Chapter 14. Serial Interface with Time-Slot Assigner

14-9

Part IV. Communications Processor Module

14.4.1 One Multiplexed Channel with Static Frames

The example in Figure 14-5 shows one of many possible settings. With this conÞguration,
the SIx RAM has 256 entries for transmit data and strobe routing and 256 entries for receive
data and strobe routing. This conÞguration should be chosen only when one TDM is
required and the routing on that TDM does not need to be dynamically changed. The
number of entries available in the SIx RAM is determined by the user.

Figure 14-5. One TDM Channel with Static Frames and Independent Rx and Tx

Routes

14.4.2 One Multiplexed Channel with Dynamic Frames

In the conÞguration shown in Figure 14-6, one multiplexed channel has 256 entries for
transmit data and strobe routing and 256 entries for receive data and strobe routing. Each
RAM has two sections, the current-route RAM and a shadow RAM for changing serial
routing dynamically.

After programming the shadow RAM, the user sets SIxCMDR[CSRxn] for the associated
channel. When the next frame sync arrives, the SI automatically exchanges the current-
route RAM for the shadow RAM. See Section 14.4.5, ÒStatic and Dynamic Routing.Ó

256 Entries

TXa

Route

Framing Signals

L1TCLKax
L1TSYNCax

SIx RAM address:

256 Entries

RXa

Route

511

1535

1024

L1RCLKax
L1RSYNCax

(16 bits wide)