h8s-2161b Renesas Electronics Corporation., h8s-2161b Datasheet - Page 193

• Manufacturer Part Number: h8s-2161b
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

6.5.4
When accessing the external address space, this LSI can extend the bus cycle by inserting one or
more wait states (T
wait insertion using the WAIT pin, and the combination of program wait and the WAIT pin.
Program Wait Mode: A specified number of wait states T
between the T
the settings of the WC1 and WC0 bits in WSCR.
Pin Wait Mode: A specified number of wait states T
T
the WC1 and WC0 bits. If the WAIT pin is low at the falling edge of in the last T
another T
This is useful when inserting four or more T
be inserted for each external device.
Pin Auto-Wait Mode: A specified number of wait states T
between the T
settings of the WC1 and WC0 bits if the WAIT pin is low at the falling edge of in the last T
state. Even if the WAIT pin is held low, T
of states.
This function enables the low-speed memory interface only by inputting the chip select signal to
the WAIT pin.
Figure 6.13 shows an example of wait state insertion timing in pin wait mode.
The settings after a reset are: 3-state access, 3 program wait insertion, and WAIT pin input
disabled.
2
state and T
W
Wait Control
state is inserted. If the WAIT pin is held low, T
3
2
2
state when accessing the external address space always according to the settings of
state and T
state and T
W
). There are three ways of inserting wait states: Program wait insertion, pin
3
3
state when accessing the external address space always according to
state when accessing the external address space according to the
W
states can be inserted only up to the specified number
W
states, or when changing the number of T
W
can be inserted automatically between the
Rev. 3.00 Mar 21, 2006 page 139 of 788
W
W
W
states are inserted until it goes high.
can be inserted automatically
can be inserted automatically
Section 6 Bus Controller (BSC)
REJ09B0300-0300
2
or T
W
W
states to
state,
2