MC68HC908LB8_05 Datasheet, PDF (25/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Chapter 2
Memory
2.1 Introduction
The CPU08 can address 64 Kbytes of memory space. The memory map, shown in Figure 2-1, includes:
• System registers
• 8192 bytes of user FLASH memory
• 128 bytes of random-access memory (RAM)
• 674 bytes of FLASH programming routines read-only memory (ROM)
• 34 bytes of user-defined vectors
2.2 Unimplemented Memory Locations
Accessing an unimplemented location can cause an illegal address reset. In the memory map
(Figure 2-1) and in register figures in this document, unimplemented locations are shaded.
2.3 Reserved Memory Locations
Accessing a reserved location can have unpredictable effects on microcontroller (MCU) operation. In the
Figure 2-1 and in register figures in this document, reserved locations are marked with the word Reserved
or with the letter R.
2.4 Register Section
Most of the control, status, and data registers are in the zero page area of $0000–$0058. Additional I/O
registers have these addresses:
• $FE00; break status register, BSR
• $FE01; SIM reset status register, SRSR
• $FE02; break auxiliary register, BRKAR
• $FE03; break flag control register, BFCR
• $FE04; interrupt status register 1, INT1
• $FE05; interrupt status register 2, INT2
• $FE06; reserved
• $FE07; reserved
• $FE08; FLASH control register, FLCR
• $FE09; break address register high, BRKH
• $FE0A; break address register low, BRKL
• $FE0B; break status and control register, BRKSCR
• $FE0C; LVI status register, LVISR
• $FF7E; FLASH block protect register, FLBPR
MC68HC908LB8 Data Sheet, Rev. 1
Freescale Semiconductor
25