mc68331cpv20b1 Freescale Semiconductor, Inc, mc68331cpv20b1 Datasheet - Page 107

• Manufacturer Part Number: mc68331cpv20b1
• Description: Mc68331 32 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

5.2.5 Vector Base Register (VBR)
5.3 Memory Organization
MC68331
USER’S MANUAL
The VBR contains the base address of the 1024-byte exception vector table, consist-
ing of 256 exception vectors. Exception vectors contain the memory addresses of rou-
tines that begin execution at the completion of exception processing. Refer to 5.9
Exception Processing for more information on the VBR and exception processing.
Memory is organized on a byte-addressable basis in which lower addresses corre-
spond to higher order bytes. For example, the address N of a long-word data item cor-
responds to the address of the most significant byte of the highest order word. The
address of the most significant byte of the low-order word is N + 2, and the address of
the least significant byte of the long word is N + 3. The CPU32 requires long-word and
word data and instructions to be aligned on word boundaries (refer to Figure 5-6).
Data misalignment is not supported.
Freescale Semiconductor, Inc.
For More Information On This Product,
CENTRAL PROCESSING UNIT
Go to: www.freescale.com
5-7
5