h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 164

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 7 Bus Controller (BSC)
Pin Wait Insertion: Setting the WAITE bit to 1 in BCRH enables wait input by means of the
WAIT pin. When an external address space is accessed in this state, a program wait is first
inserted in accordance with the settings in WCRH and WCRL. If the WAIT pin is low at the
falling edge of φ in the last T
T
when changing the number of T
bit setting applies to all areas. Figure 7.13 shows an example of wait state insertion timing.
The settings after a power-on reset are: 3-state access, insertion of three program wait states, and
WAIT input disabled.
Rev. 2.00 Dec. 05, 2005 Page 126 of 724
REJ09B0200-0200
w
states are inserted until it goes high. This is useful when inserting four or more T
Read
Write
Note:
Downward arrows indicate the timing of WAIT pin sampling.
WAIT
Address bus
AS
RD
Data bus
HWR, LWR
Data bus
φ
Figure 7.13 Example of Wait State Insertion Timing
2
or T
w
states to be inserted for different external devices. The WAITE
w
T
state, another T
1
By program wait
T
2
w
state is inserted. If the WAIT pin is held low,
T
w
Write data
By WAIT pin
T
w
T
w
Read data
w
states, or
T
3