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Address bus
AS
RD
HWR, LWR
Data bus
Figure 2-20 Pin States during On-Chip Supporting Module Access
2.9.4
External Address Space Access Timing
The external address space is accessed with an 8-bit or 16-bit data bus width in a two-state or
three-state bus cycle. In three-state access, wait states can be inserted. For further details, refer to
section 7, Bus Controller.
2.10
Usage Note
2.10.1
TAS Instruction
Only register ER0, ER1, ER4, or ER5 should be used when using the TAS instruction. The TAS
instruction is not generated by the Hitachi H8S and H8/300 series C/C++ compilers. If the TAS
instruction is used as a user-defined intrinsic function, ensure that only register ER0, ER1, ER4, or
ER5 is used.
66
Bus cycle
T1
Unchanged
High
High
High
High-impedance state
T2
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