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16
When accessing an extended external area, the wait controller controls the number of wait cycles
to be inserted in bus cycles based on the number of wait cycles set by software and those entered
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from the WAIT pin.
The number of wait cycles that can controlled in software is 1 to 4. (For external access, bus cycles
with 1 wait cycle are the shortest bus cycle.)
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When the WAIT pin input is sampled low in the last cycle of internal wait cycles set by software, the
wait cycle is extended as long as the WAIT signal is held low. Then when the WAIT signal is
released back high, the wait cycle is terminated and the next new bus cycle is entered into.
Table 16.1.2 Number of Wait Cycles that Can be Set by the Wait Controller
Extended
Address
External Area
CS0 area
H'0010 0000 - H'001F FFFF
(External extension mode)
H'0000 0000 - H'001F FFFF
(Processor mode)
CS1 area
H'0020 0000 - H'003F FFFF
(External extension mode
and processor mode)
16.1 Outline of the Wait Controller
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Number of Wait Cycles Inserted
One to 4 wait cycles set by software + any number of
wait cycles entered from WAIT pin
(However, wait cycles set by software have priority.)
One to 4 wait cycles set by software + any number of
wait cycles entered from WAIT pin
(However, wait cycles set by software have priority.)
16-3
WAIT CONTROLLER
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Ver.0.10
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