s908qc16g0cdte Freescale Semiconductor, Inc, s908qc16g0cdte Datasheet - Page 21

• Manufacturer Part Number: s908qc16g0cdte
• Description: M68hc08 Family Of 8-bit Microcontroller Units Mcus
• 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 is shown
in
Figure
2-1.
2.2 Unimplemented Memory Locations
Executing code from an unimplemented location will cause an illegal address reset. In
Figure
2-1,
unimplemented locations are shaded.
2.3 Reserved Memory Locations
Accessing a reserved location can have unpredictable effects on MCU operation. In
Figure
2-1, reserved
locations are marked with the word reserved or with the letter R.
2.4 Direct Page Registers
Figure 2-2
shows the memory mapped registers of the MC68HC08QY/QT Family. Registers with
addresses between $0000 and $00FF are considered direct page registers and all instructions including
those with direct page addressing modes can access them. Registers between $0100 and $FFFF require
non-direct page addressing modes. See
Chapter 7 Central Processor Unit (CPU)
for more information on
addressing modes.
2.5 Unused ROM Locations
Any location in the ROM memory map that is not specified in the user supplied S-record will be factory
programmed to an $83, which is an SWI opcode. The user should provide an interrupt service routine
address at the SWI interrupt vector ($FFFC/D) that points to an appropriate error routine.
MC68HC08QY/QT Family Data Sheet, Rev. 2
Freescale Semiconductor
21