HD64F2149 Datasheet, PDF (174/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Bit 5
ABW
0
1
Description
External memory space is designated as 16-bit access space
External memory space is designated as 8-bit access space
(Initial value)
Bit 4—Access State Control (AST): Specifies whether the external memory space is 2-state
access space or 3-state access space, and simultaneously enables or disables wait state insertion.
Bit 4
AST
0
1
Description
External memory space is designated as 2-state access space
Wait state insertion in external memory space accesses is disabled
External memory space is designated as 3-state access space
Wait state insertion in external memory space accesses is enabled
(Initial value)
Bits 3 and 2—Wait Mode Select 1 and 0 (WMS1, WMS0): These bits select the wait mode
when external memory space is accessed while the AST bit is set to 1.
Bit 3
WMS1
0
1
Bit 2
WMS0
0
1
0
1
Description
Program wait mode
Wait-disabled mode
Pin wait mode
Pin auto-wait mode
(Initial value)
Bits 1 and 0—Wait Count 1 and 0 (WC1, WC0): These bits select the number of program wait
states when external memory space is accessed while the AST bit is set to 1.
Bit 1
WC1
0
1
Bit 0
WC0
0
1
0
1
Description
No program wait states are inserted
1 program wait state is inserted in external memory space accesses
2 program wait states are inserted in external memory space accesses
3 program wait states are inserted in external memory space accesses
(Initial value)
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