Implicit Bus Ownership Arbitration Timing - Motorola M68060 User Manual

BUS
ARBITRATION
STATE
BCLK
A31–A0
TRANSFER
ATTRIBUTES
TS
TA
D31–D0
BR
BG
BB
BTT
AM_BR*
AM_BG*
* AM indicates the alternate bus master.
Figure 7-45. Implicit Bus Ownership Arbitration Timing
In addition, the snoop address on A31–A0 is again registered on the next CLK (not BCLK)
rising edge. For proper operation, the snoop addresses registered on these two separate
occasions must be consistent. Only normal and MOVE16 bus transfers can be snooped.
The MC68060 then examines the address of the transfer and invalidates the line in its
caches in which the address matches. This process is done quietly without external indica-
tion that a cache entry has been invalidated. Note that when snooping is enabled and an
entry matches in the MC68060 caches, the entry is invalidated regardless of the state of the
R/W signal, transfer size, or whether or not the line has clean or dirty data. If SNOOP is
negated, no snooping is done, and no lines in the caches are invalidated.
MOTOROLA
AM-EX AM-EX AM-EX IM-OWN
C1 C2 C3
ALTERNATE
MASTER
M68060 USER'S MANUAL
IM-OWN EX-OWN EX-OWN
C4 C5 C6
BUS
BUS OWNED
IMPLICITLY
AND ACTIVE
OWNED
PROCESSOR
Bus Operation
EX-OWN EX-OWN
C7 C8 C9
BUS OWNED
AND IDLE
7-69