118
Pin Wait Mode 0: The wait state controller is disabled. Wait states can only be inserted by
WAIT
pin control. During access to an external three-state-access area, if the
WAIT
pin is low at the fall
of the system clock (ø) in the T
2
state, a wait state (T
W
) is inserted. If the
WAIT
pin remains low,
wait states continue to be inserted until the
WAIT
signal goes high. Figure 6-5 shows the timing.
ø
pin
Address bus
Data bus
AS
RD
WR
Data bus
T
1
T
2
T
W
T
W
T
3
Inserted by signal
Write data
*
*
*
Read data
Read
access
Write
access
External address
WAIT
WAIT
Note:
*
Arrows indicate time of sampling of the
WAIT
pin.
Figure 6-5 Pin Wait Mode 0