MPC8280 datasheet(701/1386 Pages) FREESCALE

Part #	MPC8280

Description	PowerQUICC??II Family Reference Manual

PDF	1386 Pages

Scroll/Zoom	100%

Manufacturer	FREESCALE [Freescale Semiconductor, Inc]

Direct Link	http://www.freescale.com

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701 / 1386 page

Serial Communications Controllers (SCCs)

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

20-21

20.3.6

Digital Phase-Locked Loop (DPLL) Operation

Each SCC channel includes a digital phase-locked loop (DPLL) for recovering clock information from a

received data stream. For applications that provide a direct clock source to the SCC, the DPLL can be

bypassed by selecting 1x mode for GSMR_L[RDCR, TDCR]. If the DPLL is bypassed, only NRZ or

NRZI encodings are available. The DPLL must not be used when an SCC is programmed to Ethernet and

is optional for other protocols. Figure 20-13 shows the DPLL receiver block; Figure 20-14 shows the

transmitter block diagram.

Figure 20-13. DPLL Receiver Block Diagram

DPLL

HSRCLK

RXD

RINV

TSNC

EDGE

RDCR

RENC

Receiver

Carrier SNC

Decoded Data

Hunting

Noise

Recovered Clock

HSRCLK

RCLK

1x Mode

SCCR Data

1x Mode

CLK

HSRCLK

RXD

RINV

RENC

≠ NRZI

MPC8280 Datasheet(PDF) 701 Page - Freescale Semiconductor, Inc