MC68HC908JL8 MOTOROLA [Motorola, Inc], MC68HC908JL8 Datasheet - Page 47

• Manufacturer Part Number: MC68HC908JL8
• Description: Motorola reserves the right to make changes without further notice to any products herein
• Manufacturer: MOTOROLA [Motorola, Inc]

3.1 Contents
3.2 Introduction
3.3 Functional Description
MC68HC908JL8
MOTOROLA
Technical Data – MC68HC908JL8
NOTE:
NOTE:
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Rev. 2.0
Section 3. Random-Access Memory (RAM)
3.2
3.3
This section describes the 256 bytes of RAM.
Addresses $0060 through $015F are RAM locations. The location of the
stack RAM is programmable. The 16-bit stack pointer allows the stack to
be anywhere in the 64-Kbyte memory space.
For correct operation, the stack pointer must point only to RAM
locations.
Within page zero are 160 bytes of RAM. Because the location of the
stack RAM is programmable, all page zero RAM locations can be used
for 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 efficiently all page zero RAM locations. 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.
For M6805 compatibility, the H register is not stacked.
Freescale Semiconductor, Inc.
For More Information On This Product,
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Random-Access Memory (RAM)
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Technical Data
47