XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 63

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Technical Data — MC68HC908AZ60A
3.1 Contents
3.2 Introduction
3.3 Functional Description
MC68HC908AZ60A — Rev 2.0
MOTOROLA
NOTE:
3.2
3.3
This section describes the 2048 bytes of random-access memory
(RAM).
Addresses $0050 through $044F and $0A00 through $0DFF are RAM
locations. The location of the stack RAM is programmable with the reset
stack pointer instruction (RSP). The 16-bit stack pointer allows the stack
RAM to be anywhere in the 64K-byte memory space.
For correct operation, the stack pointer must point only to RAM
locations.
Within page zero are 176 bytes of RAM. Because the location of the
stack RAM is programmable, all page zero RAM locations can be used
for input/output (I/O) control and user data or code. When the stack
pointer is moved from its reset location at $00FF, direct addressing
mode instructions can access all page zero RAM locations efficiently.
Page zero RAM, therefore, provides ideal locations for frequently
accessed global variables.
Before processing an interrupt, the CPU uses five bytes of the stack to
save the contents of the CPU registers.
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Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
RAM
Section 3. RAM
Technical Data
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