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Section 6 Bus Controller
• Pin Auto-Wait Mode
If the WAIT pin is low, the number of wait states (T
inserted.
In pin auto-wait mode, if the WAIT pin is low at the fall of the system clock (φ) in the T
the number of wait states (T
states are inserted even if the WAIT pin remains low. Pin auto-wait mode can be used for an
easy interface to low-speed memory, simply by routing the chip select signal to the WAIT pin.
Figure 6.14 shows the timing when the wait count is 1.
φ
WAIT
Address bus
AS
RD
Read
access
Data bus
HWR
, LWR
Write
access
Data bus
Note:
Arrows indicate time of sampling of the
*
Rev. 3.00 Mar 21, 2006 page 134 of 814
REJ09B0302-0300
) selected by bits WC1 and WC0 are inserted. No additional wait
W
T
T
T
1
2
3
*
External address
Read data
Write data
WAIT
Figure 6.14 Pin Auto-Wait Mode
) selected by bits WC1 and WC0 are
W
T
T
1
2
*
External address
Write data
pin.
state,
2
T
T
W
3
Read data
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