HD6432633 Datasheet, PDF (258/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

7.4.5 Wait Control
When accessing external space, the H8S/2633 Series can extend the bus cycle by inserting one or
more wait states (T_w). There are two ways of inserting wait states: program wait insertion and pin
wait insertion using the WAIT pin.
Program Wait Insertion
From 0 to 3 wait states can be inserted automatically between the T₂ state and T₃ state on an
individual area basis in 3-state access space, according to the settings of WCRH and WCRL.
Pin Wait Insertion
Setting the WAITE bit in BCRL to 1 enables wait insertion by means of the WAIT pin. Program
wait insertion is first carried out according to the settings in WCRH and WCRL. Then, if the
WAIT pin is low at the falling edge of ø in the last T₂ or T_w state, a T_w state is inserted. If the
WAIT pin is held low, T_w states are inserted until it goes high.
This is useful when inserting four or more T_w states, or when changing the number of T_w states for
different external devices.
The WAITE bit setting applies to all areas.
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