Intel 80386 Reference Manual page 47

ClK2 [
(82384 ClK) [
8EO# - 8E3# [
A2-A31,
M/IO#,D/C#
W/R# [
ADS# [
NA# [
READY# [
00- 031 [
LOCAL BUS INTERFACE
IDLE CYCLE 1
NON-PIPELINED
(WRITE)
TI
T1 T2 T1
CYCLE 2
NON-PIPELINEO
(READ)
CYCLE 3
PIPELINEO
(WRITE)
CYCLE 4
PIPELINED
(READ)
T2 T2P T1 P
T2P T1 P T21
IDLE
TI
Following any idle bus state (Ti), addresses are non-pipelined. Within non-pipelined bus cycles, NA'" is only sampled during wait states.
Therefore, to begin address pipelining during a group of non-pipelined bus cycles requires a non-pipelined cycle with at least one wait state
(Cycle 2 above).
23t630-20
Figure 3-10. Pipelined Address Cycles
The first bus cycle after an idle bus state is always non-pipelined. To initiate address pipelin-
ing, this cycle must be extended by at least one eLK cycle so that the address and status
can be output before the end of the cycle, Subsequent cycles can be pipelined as long as no
idle bus cycles occur,
NA# is sampled at the start of Phase 2 of any eLK cycle in which ADS# is not active,
specifically,
• The second eLK cycle of a non-pipelined address cycle
• The first eLK cycle of a pipelined address cycle
• Any wait state of a non-pipelined address or pipelined address cycle unless NA# has
already been sampled active
3-16