MC68040RC25A Datasheet, PDF (204/442 Pages) Motorola, Inc – Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.
illustrated, which results in a memory access having the equivalent of two wait states.
Variations in the timing required by snooping logic to access the caches can delay the
negation of MI by up to two additional clocks. External logic must ensure that the
termination signals negate at all rising BCLK edges in which MI is asserted. Otherwise, if
one of the termination signals is asserted, either the M68040 ignores all termination
signals, reading them as negated, or the M68040 exhibits improper operation.
C1
C2
C3
C4
C5
C6
BCLK
SC1–SC0
A31–A0
SIZ1, SIZ0
TT1, TT0
R/W
TS
MI
TA
D31–D0
BR
BG
BB
AM_BR*
AM_BG*
ALTERNATE
MASTER
* AM indicates the alternate bus master.
Undefined
PROCESSOR
Figure 7-41. Snoop Access with Memory Response
7-62
M68040 USER’S MANUAL
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