Wait Control - Renesas H8S Series Hardware Manual

6.4.5

Wait Control

When accessing external space, the H8S/2357 Group can extend the bus cycle by inserting one or more wait states (T ).
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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 T state and T state on an
2 3
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
state is inserted. If the WAIT pin is held low, T
edge of ø in the last T or T state, a T states are inserted until it goes
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high.
This is useful when inserting four or more T states, or when changing the number of T states for different external
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devices.
The WAITE bit setting applies to all areas.
Rev.6.00 Oct.28.2004 page 136 of 1016
REJ09B0138-0600H