Freescale Semiconductor, Inc.
Technical Data — MC68HC705C8A
Section 2. Memory
2.1 Contents
2.2
2.3
2.4
2.5
2.6
2.7
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Memory Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Input/Output (I/O) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
EPROM/OTPROM (PROM) . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Bootloader ROM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
2.2 Introduction
2.3 Memory Map
This section describes the organization of the on-chip memory.
The central processor unit (CPU) can address eight Kbytes of memory
and input/output (I/O) registers. The program counter typically advances
one address at a time through memory, reading the program instructions
and data. The programmable read-only memory (PROM) portion of
memory — either one-time programmable read-only memory
(OTPROM) or erasable, programmable read-only memory
(EPROM) — holds the program instructions, fixed data, user-defined
vectors, and interrupt service routines. The random-access memory
(RAM) portion of memory holds variable data.
I/O registers are memory-mapped so that the CPU can access their
locations in the same way that it accesses all other memory locations.
The shared stack area is used during processing of an interrupt or
MC68HC705C8A — Rev. 3
MOTOROLA
Technical Data
Memory
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