MC908MR16CFUE Datasheet, PDF (25/282 Pages) Freescale Semiconductor, Inc – On-chip programming firmware for use with host personal computer, Clock generator module (CGM)

Chapter 2
Memory
2.1 Introduction
The central processor unit (CPU08) can address 64 Kbytes of memory space. The memory map, shown
in Figure 2-1, includes:
• 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)
2.2 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 (Figure 2-1) and in the I/O register summary (Figure 2-2) reserved
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.
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor
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