r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 230

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 6 Bus Controller (BSC)
6.5.4
When accessing external space, this LSI can extend the bus cycle by inserting one or more wait
states (T
insertion using the WAIT pin.
(1)
From 0 to 7 wait states can be inserted automatically between the T
individual area basis in 3-state access space, according to the settings in WTCRA and WTCRB.
(2)
Setting the WAITE bit to 1 in BCR enables wait input by means of the WAIT pin. When external
space is accessed in this state, a program wait is first inserted in accordance with the settings in
WTCRA and WTCRB. If the WAIT pin is low at the falling edge of φ in the last T
another T
This is useful when inserting seven or more T
be inserted for different external devices. The WAITE bit setting applies to all areas. Figure 6.18
shows an example of wait state insertion timing.
The settings after a reset are: 3-state access, insertion of 7 program wait states, and WAIT input
disabled.
Rev. 1.00 Sep. 19, 2008 Page 200 of 1342
REJ09B0467-0100
Program Wait Insertion
Pin Wait Insertion
w
). There are two ways of inserting wait states: program wait insertion and pin wait
w
Wait Control
state is inserted. If the WAIT pin is held low, T
w
states, or when changing the number of T
w
states are inserted until it goes high.
2
state and T
3
state on an
2
or T
w
w
state,
states to