86
6.2.3
Break Bus Cycle Register (BBR)
The break bus cycle register (BBR) is a 16-bit read/write register that selects the following four
break conditions:
•
CPU cycle or DMA cycle
•
Instruction fetch or data access
•
Read or write
•
Operand size (byte, word, longword).
A reset initializes BBR to H'0000. It is not initialized in standby mode.
Bit:
15
14
13
12
11
10
9
8
Bit name:
—
—
—
—
—
—
—
—
Initial value:
0
0
0
0
0
0
0
0
R/W:
—
—
—
—
—
—
—
—
Bit:
7
6
5
4
3
2
1
0
Bit name:
CD1
CD0
ID1
ID0
RW1
RW0
SZ1
SZ0
Initial value:
0
0
0
0
0
0
0
0
R/W:
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
•
Bits 15–8 (Reserved): These bits are always read as 0. The write value should always be 0.
•
Bits 7 and 6 (CPU Cycle/DMA Cycle Select (CD1 and CD0)): CD1 and CD0 select whether to
break on CPU and/or DMA bus cycles.
Bit 7: CD1
Bit 6: CD0
Description
0
0
No break interrupt occurs
(Initial value)
1
Break only on CPU cycles
1
0
Break only on DMA cycles
1
Break on both CPU and DMA cycles
Summary of Contents for HD6417032
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Page 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
Page 578: ...543 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 62 Self Refresh ...
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