
Communication Processor Module
MOTOROLA
MPC823 USER’S MANUAL
16-115
SERIAL
I/F
COMMUNICATION
16
PROCESSOR
MODULE
16.7.1 Features
The top-level features of the serial interface are the time-slot assigner and NMSI. The
time-slot assigner has the following main features:
Ability to connect to an independent TDMA channel
Independent, programmable transmit and receive routing paths
Independent transmit and receive frame syncs
Independent transmit and receive clocks
Selection of rising/falling clock edges for the frame sync and data bits
Supports 1
× and 2× input clocks (1 or 2 clocks per data bit)
Selectable delay (0–3 bits) between frame sync and frame start
Eight programmable strobe outputs (LST[1-4] used for receive (RX) RAM while
LST[5-8] is used for transmit (TX) RAM)
1- or 8-bit resolution in routing, masking, and strobe selection
Supports frames up to 8,192 bits long
Internal routing and strobe selection can be dynamically programmed
Supports automatic echo and loopback mode for the TDMA
The NMSI has the following main features:
The serial communication controller (SCC2) and each serial management controller
(SMC) can be independently programmed to work with its own set of pins in a
nonmultiplexed manner
The serial communication controller can have its own set of modem control pins
Each serial management controller can have its own set of pins
The serial communication controller, universal serial bus, and each serial management
controller can derive clocks externally from a bank of four clock pins or a bank of four
baud rate generators
16.7.2 Configuring the Time-Slot Assigner
The time-slot assigner implements both internal route selection and time-division
multiplexing for multiplexed serial channels. It supports the serial bus rate and format for
most standard TDM buses, including the T1 and CEPT highways, pulse code modulation
(PCM) highway, and ISDN buses in both basic and primary rates. The two popular ISDN
basic rate buses—interchip digital link and general circuit interface (also known as IOM-2)
are supported.