Intel 386

6-21
BUS INTERFACE UNIT
Figure 6-8. Pipelined Address Cycles
A2477-03
LOCK#
D15:0
Valid 2
Valid 3 Valid 4
CLK2
BHE#, BLE#, A25:1,
M/IO#, D/C#
Valid3
Valid4
Valid2
Valid1
W/R#
ADS#
NA#
T1P T2P T2P T1P T2 T2P T1P T2i T2P T1P
Cycle 1
Pipelined
(Write)
[Late Ready]
Cycle 2
Non-pipelined
(Read)
Cycle 3
Pipelined
(Write)
[Late Ready]
Cycle 4
Pipelined
(Read)
CLKOUT
ADS# is asserted as
soon as the CPU has
another bus cycle to
perform, which is not
always immediately
after NA# is asserted.
As long as the CPU enters the T2P
state during Cycle 3, address
pipelining is maintained in Cycle 4.
Note ADS# is
asserted in
every T2P state.
In
2
Asserting NA# more
than once during
any cycle has no
additional effects
NA# could have been asserted in T1P
if desired. Assertion now is the latest
time possible to allow the CPU to enter
T2P state to maintain pipelining in cycle 3.
READY#
RD#
WR#
LBA#
BS8#
Out 1
Out
Valid 1
Out 3
T2