MC68HC705P6ACDW Freescale Semiconductor, MC68HC705P6ACDW Datasheet - Page 68

• Manufacturer Part Number: MC68HC705P6ACDW
• Description: IC MCU 2.1MHZ 4.5K OTP 28-SOIC
• Manufacturer: Freescale Semiconductor
• Series: HC05r

Specifications of MC68HC705P6ACDW

• Core Processor: HC05
• Core Size: 8-Bit
• Speed: 2.1MHz
• Connectivity: SIO
• Peripherals: POR, WDT
• Number Of I /o: 21
• Program Memory Size: 4.5KB (4.5K x 8)
• Program Memory Type: OTP
• Ram Size: 176 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 4x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Data Bus Width: 8 bit
• Data Ram Size: 176 B
• Maximum Clock Frequency: 2.1 MHz
• Number Of Programmable I/os: 37
• Number Of Timers: 16 bit
• Operating Supply Voltage: 3.3 V to 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No RoHS Version Available

Central Processor Unit (CPU) Core
12.2.2 Index Register
The index register shown in
In indexed addressing with no offset, the index register contains the low byte of the operand address, and
the high byte is assumed to be $00. In indexed addressing with an 8-bit offset, the CPU finds the operand
address by adding the index register contents to an 8-bit immediate value. In indexed addressing with a
16-bit offset, the CPU finds the operand address by adding the index register contents to a 16-bit
immediate value.
The index register can also serve as an auxiliary accumulator for temporary storage. The index register
is unaffected by a reset of the device.
12.2.3 Stack Pointer
The stack pointer shown in
than 64 Kbytes, the unimplemented upper address lines are ignored. The stack pointer contains the
address of the next free location on the stack. During a reset or the reset stack pointer (RSP) instruction,
the stack pointer is set to $00FF. The stack pointer is then decremented as data is pushed onto the stack
and incremented as data is pulled from the stack.
When accessing memory, the 10 most significant bits are permanently set to 0000000011. The six least
significant register bits are appended to these 10 fixed bits to produce an address within the range of
$00FF to $00C0. Subroutines and interrupts may use up to 64 ($40) locations. If 64 locations are
exceeded, the stack pointer wraps around and writes over the previously stored information. A subroutine
call occupies two locations on the stack and an interrupt uses five locations.
12.2.4 Program Counter
The program counter shown in
less than 64 Kbytes, the unimplemented upper address lines are ignored. The program counter contains
the address of the next instruction or operand to be fetched.
Normally, the address in the program counter 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.
12.2.5 Condition Code Register
The CCR shown in
instruction just executed. The fifth bit is the interrupt mask. These bits can be individually tested by a
program, and specific actions can be taken as a result of their state. The condition code register should
be thought of as having three additional upper bits that are always ones. Only the interrupt mask is
affected by a reset of the device. The following paragraphs explain the functions of the lower five bits of
the condition code register.
H — Half Carry Bit
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When the half-carry bit is set, it means that a carry occurred between bits 3 and 4 of the accumulator
during the last ADD or ADC (add with carry) operation. The half-carry bit is required for binary-coded
decimal (BCD) arithmetic operations.
Indexed addressing
Temporary storage
Figure 12-1
MC68HC705P6A Advance Information Data Sheet, Rev. 2.1
Figure 12-1
Figure 12-1
Figure 12-1
is a 5-bit register in which four bits are used to indicate the results of the
is a 16-bit register internally. In devices with memory maps less
is an 8-bit register that can perform two functions:
is a 16-bit register internally. In devices with memory maps
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