HC08KL8GRSSLASHD datasheet(61/256 Pages) NXP

61 / 256 page

Central Processor Unit (CPU)

CPU Registers

MC68HC08KL8 — Rev. 2.0

General Release Specification

Central Processor Unit (CPU)

6.4.3 Stack Pointer

The stack pointer is a 16-bit register that contains the address of the next

location on the stack. During a reset, the stack pointer is preset to

$00FF. The reset stack pointer (RSP) instruction also sets the least

significant byte (LSB) to $FF but does not affect the most significant byte

(MSB). The stack pointer decrements as data is pushed onto the stack

and increments as data is pulled from the stack.

In the stack pointer 8-bit offset and 16-bit offset addressing modes, the

stack pointer can function as an index register to access data on the

stack. The CPU uses the contents of the stack pointer to determine the

conditional address of the operand.

NOTE:

The location of the stack is arbitrary and may be relocated anywhere in

RAM. Moving the SP out of page zero ($0000 to $00FF) frees direct

address (page zero) space. For correct operation, the stack pointer must

point only to RAM locations.

Bit

Read:

Write:

Reset:

Figure 6-4. Stack Pointer (SP)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC08KL8GRS/D Datasheet(PDF) 61 Page - NXP Semiconductors