XC68HC705JJ7 Motorola, XC68HC705JJ7 Datasheet - Page 48

• Manufacturer Part Number: XC68HC705JJ7
• Description: MICROCONTROLLER
• Manufacturer: Motorola

Central Processor Unit (CPU)
3.6 Program Counter
3.7 Condition Code Register
Advance Information
48
Reset:
The program counter is a 16-bit register that contains the address of the
next instruction or operand to be fetched as shown in
three most significant bits of the program counter are ignored internally
and appear as 111 during stacking and subroutine calls.
Normally, the address in the program counter automatically increments
to the next sequential memory location every time an instruction or
operand is fetched. Jump, branch, and interrupt operations load the
program counter with an address other than that of the next sequential
location.
The condition code register is an 8-bit register whose three most
significant bits are permanently fixed at 111 as shown in
condition code register contains the interrupt mask and four flags that
indicate the results of the instruction just executed. The following
paragraphs describe the functions of the condition code register.
Read:
Write:
Reset:
Read:
Write:
Bit
15
1
0
Bit 7
U = Unaffected
1
1
14
1
0
Central Processor Unit (CPU)
Figure 3-6. Condition Code Register (CCR)
13
1
0
Figure 3-5. Program Counter (PC)
6
1
1
12
11
5
1
1
10
Loaded with vector from $1FFE and $1FFF
9
MC68HC705JJ7 • MC68HC705JP7 — REV 4
H
U
4
8
7
3
1
I
6
5
N
U
2
4
Figure
Figure
3
C
U
1
2
MOTOROLA
3-5. The
3-6. The
1
Bit 0
U
Z
Bit
0