HD64F2149 Datasheet, PDF (144/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

5.2.9 Break Address Registers A, B, C (BARA, BARB, BARC)
Bit
7
6
5
4
3
2
1
0
BARA
A23
A22
A21
A20
A19
A18
A17
A16
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit
7
6
5
4
3
2
1
0
BARB
A15
A14
A13
A12
A11
A10
A9
A8
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bit
7
6
5
4
3
2
1
0
BARC
A7
A6
A5
A4
A3
A2
A1
—
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
BAR consists of three 8-bit readable/writable registers (BARA, BARB, and BARC), and is used to
specify the address at which an address break is to be executed.
Each of the BAR registers is initialized to H'00 by a reset and in hardware standby mode. They are
not initialized in software standby mode.
BARA Bits 7 to 0—Address 23 to 16 (A23 to A16)
BARB Bits 7 to 0—Address 15 to 8 (A15 to A8)
BARC Bits 7 to 1—Address 7 to 1 (A7 to A1)
These bits specify the address at which an address break is to be executed. BAR bits A23 to A1
are compared with internal address bus lines A23 to A1, respectively.
The address at which the first instruction byte is located should be specified as the break address.
Occurrence of the address break condition may not be recognized for other addresses.
In normal mode, no comparison is made with address lines A23 to A16.
BARC Bit 0—Reserved: This bit cannot be modified and is always read as 0.
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