mc68hc908mr32 Freescale Semiconductor, Inc, mc68hc908mr32 Datasheet - Page 25

• Manufacturer Part Number: mc68hc908mr32
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 2
Memory
2.1 Introduction
The central processor unit (CPU08) can address 64 Kbytes of memory space. The memory map, shown
in
2.2 Unimplemented Memory Locations
Some addresses are unimplemented. Accessing an unimplemented address can cause an illegal address
reset. In the memory map and in the input/output (I/O) register summary, unimplemented addresses are
shaded.
Some I/O bits are read only; the write function is unimplemented. Writing to a read-only I/O bit has no
effect on microcontroller unit (MCU) operation. In register figures, the write function of read-only bits is
shaded.
Similarly, some I/O bits are write only; the read function is unimplemented. Reading of write-only I/O bits
has no effect on MCU operation. In register figures, the read function of write-only bits is shaded.
2.3 Reserved Memory Locations
Some addresses are reserved. Writing to a reserved address can have unpredictable effects on MCU
operation. In the memory map
addresses are marked with the word reserved.
Some I/O bits are reserved. Writing to a reserved bit can have unpredictable effects on MCU operation.
In register figures, reserved bits are marked with the letter R.
Freescale Semiconductor
Figure
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32 Kbytes of FLASH
768 bytes of random-access memory (RAM)
46 bytes of user-defined vectors
240 bytes of monitor read-only memory (ROM)
2-1, includes:
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
(Figure
2-1) and in the I/O register summary
(Figure
2-2) reserved
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