98
ASTCR sets the number of access states for the external memory space. The number of access
states for on-chip memory and internal I/O registers is fixed regardless of the settings in ASTCR.
ASTCR is initialized to H'FF by a reset and in hardware standby mode. It is not initialized in
software standby mode.
Bits 7 to 0—Area 7 to 0 Access State Control (AST7 to AST0): These bits select whether the
corresponding area is to be designated as 2-state access space or 3-state access space.
Wait state insertion is enabled or disabled at the same time.
Bit n
ASTn
Description
0
Area n is designated as 2-state access space
Wait state insertion in area n external space access is disabled
1
Area n is designated as 3-state access space
(Initial value)
Wait state insertion in area n external space access is enabled
(n = 7 to 0)
4.2.3
Wait Control Registers A and B (WTCRA, WTCRB)
WTCRA and WTCRB are 16-bit readable/writable registers that select the number of program
wait states for each area.
Program waits are not inserted in on-chip memory or internal I/O register access.
WTCRA and WTCRB are initialized to H'7777 by a reset and in hardware standby mode. They
are not initialized in software standby mode.
WTCRA
Bit
15
14
13
12
11
10
9
8
—
W72
W71
W70
—
W62
W61
W60
Initial value
0
1
1
1
0
1
1
1
Read/Write
R
R/W
R/W
R/W
R
R/W
R/W
R/W
Bit
7
6
5
4
3
2
1
0
—
W52
W51
W50
—
W42
W41
W40
Initial value
0
1
1
1
0
1
1
1
Read/Write
R
R/W
R/W
R/W
R
R/W
R/W
R/W
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