HD6473032F16 Datasheet, PDF (162/847 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 6 Bus Controller
Wait Mode in Areas Where Wait-State Controller is Disabled: External three-state access
areas in which the wait-state controller is disabled (ASTn = 1, WCEn = 0) operate in pin wait
mode 0. The other wait modes are unavailable. The settings of bits WMS1 and WMS0 are ignored
in these areas.
• Pin Wait Mode 0
Wait states can only be inserted by WAIT pin control. During access to an external three-state-
access area, if the WAIT pin is low at the fall of the system clock (φ) in the T₂ state, a wait
state (T_W) is inserted. If the WAIT pin remains low, wait states continue to be inserted until the
WAIT signal goes high. Figure 6.12 shows the timing.
Inserted by 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
HWR, LWR
Data bus
Write data
Note: * Arrows indicate time of sampling of the WAIT pin.
Figure 6.12 Pin Wait Mode 0
Rev. 3.00 Mar 21, 2006 page 132 of 814
REJ09B0302-0300