MC68HC908JK3 MOTOROLA [Motorola, Inc], MC68HC908JK3 Datasheet - Page 55

• Manufacturer Part Number: MC68HC908JK3
• Description: MC68HC908JK1
• Manufacturer: MOTOROLA [Motorola, Inc]

6.4.4 Program Counter
6.4.5 Condition Code Register
MC68H(R)C908JL3
MOTOROLA
NOTE:
—
Rev. 1.0
The location of the stack is arbitrary and may be relocated anywhere in
RAM. Moving the SP out of page 0 ($0000 to $00FF) frees direct
address (page 0) space. For correct operation, the stack pointer must
point only to RAM locations.
The program counter is a 16-bit register that contains the address of the
next instruction or operand to be fetched.
Normally, 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.
During reset, the program counter is loaded with the reset vector
address located at $FFFE and $FFFF. The vector address is the
address of the first instruction to be executed after exiting the reset state.
The 8-bit condition code register contains the interrupt mask and five
flags that indicate the results of the instruction just executed. Bits 6 and
Reset:
Reset:
Read:
Read:
Write:
Write:
Bit
15
Bit
15
0
14
14
Central Processor Unit (CPU)
0
13
13
0
Figure 6-5. Program Counter (PC)
Figure 6-4. Stack Pointer (SP)
12
12
0
11
11
0
Loaded with Vector from $FFFE and $FFFF
10
10
0
9
9
0
8
8
0
7
7
1
6
6
1
Central Processor Unit (CPU)
5
5
1
4
4
1
3
3
1
CPU Registers
Technical Data
2
2
1
1
1
1
Bit
Bit
55
0
1
0