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6.3
Register Descriptions
Registers related to the bus controller are as follows.
• Bus control register (BCR)
• Basic area/area 1 control register (BCRA1)
• Area 2 control register (BCRA2)
• Area 3 control register (BCRA3)
6.3.1
Bus Control Register (BCR)
BCR is used to specify the external extended selection, inversion control of CS1 to CS3, AS, and
AH pins, as well as idle cycle insertion.
Bit
Bit Name
7
6
ICIS
5
4
3
2
1
PNCASH
Rev. 1.00, 09/03, page 94 of 704
Initial
Value
R/W
Description
1
R/(W)
Reserved
The initial value should not be changed.
1
R/W
Idle Cycle Insert
When external read cycle and external write cycle
continue, it selects whether idle cycle 1-state is inserted
or idle cycle is not inserted.
0: Idle cycle is not inserted
1: Idle cycle 1-state is inserted
1
R/(W)
Reserved
The initial value should not be changed.
0
R/(W)
Reserved
The initial value should not be changed.
0
R/(W)
Reserved
The initial value should not be changed.
0
R/(W)
Reserved
The initial value should not be changed.
0
R/W
Address Strobe/Hold Polarity Control
Controls output polarity of address strobe signal (AS)
and address hold signal (AH).
0: AS/AH output
1: AS/AH output
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