mc68hc05ct4fn Freescale Semiconductor, Inc, mc68hc05ct4fn Datasheet - Page 34

• Manufacturer Part Number: mc68hc05ct4fn
• Description: Mc68hc05 Family Of Microcontrollers Mcus
• Manufacturer: Freescale Semiconductor, Inc

Central Processing Unit
3.6 Stack Pointer
3.7 Program Counter
General Release Specification
NOTE:
The stack pointer contains the address of the next free location on the
stack. During an MCU reset or the reset stack pointer (RSP) instruction,
the stack pointer is set to location $00FF. The stack pointer then is
decremented as data is pushed onto the stack and incremented as data
is pulled from the stack.
When accessing memory, the seven most significant bits (MSB) are
permanently set to 0000011. These seven bits are appended to the six
least significant register bits to produce an address within the range of
$00FF to $00C0. Subroutines and interrupts may use up to 64 (decimal)
locations. If 64 locations are exceeded, the stack pointer wraps around
and loses the previously stored information. A subroutine call occupies
two locations on the stack; an interrupt uses five locations.
The program counter (PC) is a 13-bit register that contains the address
of the next byte to be fetched. .
The HC05 CPU core is capable of addressing 16-bit locations. For this
implementation, however, the addressing registers are limited to
an 8-Kbyte memory map
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
Central Processing Unit
12
12
0
0
0
0
0
7
1
PC
1
SP
MC68HC05CT4
0
0
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Rev. 2.0