MPC8280 datasheet(582/1386 Pages) FREESCALE

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Serial Interface with Time-Slot Assigner

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

15-4

Freescale Semiconductor

For the MCC route, the SI performs the following features:

•

Up to 128 independent communication channels (64-Kbps per channel)

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Arbitrary mapping of any TDM time slots

•

Can connect up to four independent TDM channels. Each TDM channel can support up to 128

channels (all four channels can support up to 128 channels together).

•

Independent mapping for receive/transmit

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Individual channel echo or loop mode

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Global echo or loop mode through the SI

15.2

Overview

The TSA implements both internal route selection and time-division multiplexing (TDM) for multiplexed

serial channels. The TSA supports the serial bus rate and format for most standard TDM buses, including

T1 and E1 highways, pulse-code modulation (PCM) highway, and the ISDN buses in both basic and

primary rates. The two popular ISDN basic rate buses (interchip digital link (IDL) and general-circuit

interface (GCI), also known as IOM-2) are supported.

Because each SI supports four TDMs, it is possible to simultaneously support a combination of up to eight

T1 or E1 lines, and basic rate or primary rate ISDN channels.

The TDMa channel can support E3 or DS-3 rates as a clear channel in a parallel-nibble interface (FCC in

HDLC mode, clock ratio 1/6) or serial interface (clock ratio 1/4).

TSA programming is independent of the protocol used. The serial controllers can be programmed for any

synchronous protocol without affecting TSA programming. The TSA simply routes programmed portions

of the received data frame from the TDM pins to the target controller, while the target controller handles

the received data in the actual protocol.

In its simplest mode, the TSA identifies the frame using one sync pulse and one clock signal provided

externally by the user. This can be enhanced to allow independent routing of the receive and transmit data

on the TDM. Additionally, the definition of a time-slot need not be limited to 8 bits or even to a single

contiguous position within the frame. Finally, the user can provide separate receive and transmit syncs as

well as clocks. Figure 15-2 shows example TSA configurations ranging from the simplest to the most

complex.

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