XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 62

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

Central Processor Unit (CPU)
3.3 CPU Registers
3.3.1 Accumulators A and B
3.3.2 Accumulator D
Data Sheet
62
Reset:
Read:
Write:
Bit 15
(A7)
D15
NOTE:
(A6)
D14
14
(A5)
D13
13
This section describes the CPU registers.
Accumulators A and B are general-purpose 8-bit accumulators that contain
operands and results of arithmetic calculations or data manipulations.
Accumulator D is the concatenation of accumulators A and B. Some instructions
treat the combination of these two 8-bit accumulators as a 16-bit double
accumulator.
The LDD and STD instructions can be used to manipulate data in and out of
accumulator D.
(A4)
D12
12
Reset:
Reset:
Read:
Read:
Write:
Write:
(A3)
D11
11
Bit 7
Bit 7
A7
B7
Figure 3-4. Accumulator D (D)
D10
(A2)
10
Central Processor Unit (CPU)
A6
B6
(A1)
6
6
D9
9
Figure 3-2. Accumulator A (A)
Figure 3-3. Accumulator B (B)
Unaffected by reset
(A0)
D8
8
A5
B5
5
5
(B7)
D7
7
Unaffected by reset
Unaffected by reset
A4
B4
4
4
(B6)
D6
6
(B5)
D5
5
A3
B3
3
3
(B4)
D4
4
M68HC12B Family — Rev. 8.0
A2
B2
2
2
(B3)
D3
3
(B2)
D2
2
A1
B1
1
1
(B1)
MOTOROLA
D1
1
Bit 0
Bit 0
A0
B0
Bit 0
(B0)
D0