MC68HC705KJ1CDW Freescale Semiconductor, MC68HC705KJ1CDW Datasheet - Page 35

• Manufacturer Part Number: MC68HC705KJ1CDW
• Description: IC MCU 4MHZ 1.2K OTP 16-SOIC
• Manufacturer: Freescale Semiconductor
• Series: HC05r

Specifications of MC68HC705KJ1CDW

• Core Processor: HC05
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 10
• Program Memory Size: 1.2KB (1.2K x 8)
• Program Memory Type: OTP
• Ram Size: 64 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -
• Connectivity: -

4.5 CPU Registers
The M68HC05 CPU contains five registers that control and monitor MCU operation:
CPU registers are not memory mapped.
4.5.1 Accumulator
The accumulator is a general-purpose 8-bit register. The CPU uses the accumulator to hold operands and
results of ALU operations.
4.5.2 Index Register
In the indexed addressing modes, the CPU uses the byte in the index register to determine the conditional
address of the operand. The index register also can serve as a temporary storage location or a counter.
4.5.3 Stack Pointer
The stack pointer is a 16-bit register that contains the address of the next location on the stack. During a
reset or after the reset stack pointer instruction (RSP), the stack pointer is preset to $00FF. The address
in the stack pointer decrements after a byte is stacked and increments before a byte is unstacked.
Freescale Semiconductor
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Accumulator
Index register
Stack pointer
Program counter
Condition code register
Reset:
Reset:
Read:
Read:
Write:
Write:
Reset:
Read:
Write:
MC68HC705KJ1 • MC68HRC705KJ1 • MC68HLC705KJ1 Data Sheet, Rev. 4.1
Bit
15
0
0
Bit 7
Bit 7
= Unimplemented
14
0
0
13
0
0
6
6
12
0
0
Figure 4-4. Stack Pointer (SP)
Figure 4-3. Index Register (X)
Figure 4-2. Accumulator (A)
11
0
0
5
5
10
0
0
Unaffected by reset
Unaffected by reset
9
0
0
4
4
8
0
0
7
1
1
3
3
6
1
1
5
1
2
2
4
1
3
1
1
1
2
1
1
1
Bit 0
Bit 0
Bit
0
1
CPU Registers
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