mcf5272 Freescale Semiconductor, Inc, mcf5272 Datasheet - Page 297

• Manufacturer Part Number: mcf5272
• Description: Mcf5272 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

Chapter 13
Physical Layer Interface Controller
(PLIC)
This chapter provides detailed information about the MCF5272’s physical layer interface
controller (PLIC), a module intended to support ISDN applications. The chapter begins
with a description of operation and a series of related block diagrams starting with a
high-level overview. Each successive diagram depicts progressively more internal detail.
The chapter then describes timing generation, the programming model, and concludes with
three application examples.
The reader is assumed to have a basic familiarity with ISDN technology and terminology.
A glossary containing many ISDN terms can be found on the web at the following URL:
http://www.tribecatech.com/isdnterm.htm.
13.1 Introduction
The physical layer interface controller (PLIC) allows the MCF5272 to connect at a physical
level with external CODECs (coder/decoder) and other peripheral devices that use either
the general circuit interface (GCI) or interchip digital link (IDL) physical layer protocols.
This module is primarily intended to facilitate designs that include ISDN (integrated
services digital network) interfaces.
The MCF5272 has four dedicated physical layer interface ports for connecting to external
ISDN transceivers, codecs, and other peripherals. There are three sets of pins for these
interfaces. Port 0 has its own dedicated set of pins. Ports 1, 2, and 3 share a set of pins.
Port 3 can also be configured to use a dedicated pin set. Ports 1, 2, and 3 always share the
same data clock (DCL).
When the ports are operated in slave mode, the PLIC can support a DCL frequency of
4.096 MHz and frame sync frequency (FSC/FSR) of 8 KHz. When in master mode, DCL
should be no greater than one-twentieth of the CPU clock (CLKIN), with a maximum
FSC/FSR of 8 KHz.
This chapter is written from the perspective of connecting to an ISDN transceiver with
8-KHz frame sync. The MCF5272 PLIC has four ports, port 0 – port 3, connected through
three pin sets, numbered 0, 1, and 3. A port can service, read, or write any 2B + D channel.
As shown in Figure 13-1, port 0 connects through pin set 0, and ports 1 and 2 both connect
MOTOROLA
Chapter 13. Physical Layer Interface Controller (PLIC)
13-1