HD64F3039F18 Datasheet, PDF (149/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 6 Bus Controller
Pin Wait Mode 1
In all accesses to external three-state-access areas, the number of wait states (T_W) selected by bits
WC1 and WC0 are inserted. If the WAIT pin is low at the fall of the system clock (φ) in the last of
these wait states, an additional wait state is inserted. If the WAIT pin remains low, wait states
continue to be inserted until the WAIT signal goes high.
Pin wait mode 1 is useful for inserting four or more wait states, or for inserting different numbers
of wait states for different external devices.
If the wait count is 0, this mode operates in the same way as pin wait mode 0.
Figure 6.6 shows the timing when the wait count is 1 (WC1 = 0, WC0 = 1) and one additional wait
state is inserted by WAIT input.
Inserted by Inserted by
wait count WAIT signal
T₁
T₂
T_W
T_W
T₃
φ
*
*
WAIT pin
Address bus
External address
AS
Read
access
RD
Data bus
Read data
Write
access
WR
Data bus
Write data
Note: * Arrows indicate time of sampling of the WAIT pin.
Figure 6.6 Pin Wait Mode 1
Rev.3.00 Mar. 26, 2007 Page 125 of 682
REJ09B0353-0300