MPC8280 datasheet(488/1386 Pages) FREESCALE

No. de pieza	MPC8280

Descripción Electrónicos	PowerQUICC??II Family Reference Manual

PDF	1386 Pages

Scroll/Zoom	100%

Fabricante Electrónico	FREESCALE [Freescale Semiconductor, Inc]

Página de inicio	http://www.freescale.com

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488 / 1386 page

Memory Controller

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

11-68

Freescale Semiconductor

11.6.3

Clock Timing

Fields in the RAM word specify the value of the various external signals at each clock edge. The signal

timing generator causes external signals to behave according to the timing specified in the current RAM

word. Figure 11-58 and Figure 11-59 show the clock schemes of the UPMs in the memory controller for

integer and non-integer clock ratios. The clock phases shown reflect timing windows during which

generated signals can change state. If specified in the RAM, the value of the external signals can be

changed after any of the positive edges of T[1–4], plus a circuit delay time as specified in the Hardware

Specifications.

NOTE

For integer clock ratios, the widths of T1/2/3/4 are equal, for a 1:2.5 clock

ratio, T1 = 4/3*T2 and T3 = 4/3*T4, and for a 1:3.5 clock ratio, the ticks

widths are T1 = 3/2*T2 and T3 = 3/2*T4.

Figure 11-58. Memory Controller UPM Clock Scheme for Integer Clock Ratios

CLKIN

MPC8280 Datasheet(PDF) 488 Page - Freescale Semiconductor, Inc