MPC823 datasheet(28/74 Pages) MOTOROLA

28 / 74 page

Communication Processor Module

16-406

MPC823 REFERENCE MANUAL

MOTOROLA

16.11.7 The SMCx in Transparent Mode

A serial managment controller in Transparent mode is also referred to as the SMCx

Transparent controller. The following is a list of the features that the SMCx Transparent

controller does not support:

• Independent transmit and receive clocks, unless it is connected to the TDM channel of

the serial interface

• CRC generation and checking

• Full RTSx, CTSx, and CDx pins. Instead, there is a SMSYN pin for each SMC.

• Ability to transmit data on demand using the transmit on demand register

• Receiver/transmitter in transparent mode while executing another protocol

• 4-, 8-, or 16-bit Sync recognition

• Internal DPLL support

An SMCx in Transparent mode has one feature that an SCCx in Transparent mode does

not. The serial management controllers allow a data character length option of 4 to 16 bits,

whereas the SCCs allow 8 or 32 bits, depending on how the RFW bit is set in the GSMR_H

(described in Section 16.9.2 The General SCCx Mode Registers).

16.11.7.1 FEATURES. The following list summarizes the features of a serial management

controller in Transparent mode:

• Flexible data buffers

• Connects to the TDM bus using the time-slot assigner in the serial interface

• Transmits and receives transparently on its own set of pins using a sync pin to

synchronize the beginning of transmission and reception to an external event

• Programmable 4-16 character length

• Reverse data mode

• Continuous transmission and reception modes

• Four available commands

16.11.7.2 SMCx TRANSPARENT CHANNEL TRANSMISSION PROCESS. The SMCx

Transparent transmitter is designed to work with almost no intervention from the core. When

the core enables the SMCx transmitter in transparent mode, it starts transmitting idles. The

serial management controllers immediately poll the first buffer descriptor in the transmit

channel buffer descriptor ring once every character time, depending on the character length

(every 4 to 16 serial clocks). When there is a message to transmit, a serial management

controller fetches the data from memory and starts transmitting the message after

synchronization is achieved.

MPC823 Datasheet(PDF) 28 Page - Motorola, Inc