DSPIC33FJ64MC508 Microchip Technology Inc., DSPIC33FJ64MC508 Datasheet - Page 33

• Manufacturer Part Number: DSPIC33FJ64MC508
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

3.1.1
The
word-addressable blocks. Although it is treated as
24 bits wide, it is more appropriate to think of each
address of the program memory as a lower and upper
word, with the upper byte of the upper word being
unimplemented. The lower word always has an even
address, while the upper word has an odd address
(Figure 3-2).
Program memory addresses are always word-aligned
on the lower word, and addresses are incremented or
decremented by two during code execution. This
arrangement also provides compatibility with data
memory space addressing and makes it possible to
access data in the program memory space.
FIGURE 3-2:
© 2007 Microchip Technology Inc.
program
0x000001
0x000003
0x000005
0x000007
Address
msw
PROGRAM MEMORY
ORGANIZATION
memory
dsPIC33FJXXXMCX06/X08/X10 MOTOR CONTROL FAMILY
Program Memory
PROGRAM MEMORY ORGANIZATION
‘Phantom’ Byte
(read as ‘0’)
00000000
00000000
00000000
00000000
space
most significant word
is
23
organized
in
16
Instruction Width
3.1.2
All dsPIC33FJXXXMCX06/X08/X10 Motor Control
Family devices reserve the addresses between
0x00000 and 0x000200 for hard-coded program exe-
cution vectors. A hardware Reset vector is provided to
redirect code execution from the default value of the
PC on device Reset to the actual start of code. A GOTO
instruction is programmed by the user at 0x000000,
with the actual address for the start of code at
0x000002.
dsPIC33FJXXXMCX06/X08/X10 Motor Control Family
devices also have two interrupt vector tables located
from 0x000004 to 0x0000FF and 0x000100 to
0x0001FF. These vector tables allow each of the many
device interrupt sources to be handled by separate
Interrupt Service Routines (ISRs). A more detailed dis-
cussion of the interrupt vector tables is provided in
Section 6.1 “Interrupt Vector Table”.
least significant word
8
INTERRUPT AND TRAP VECTORS
0
(lsw Address)
PC Address
0x000000
0x000002
0x000004
0x000006
DS70287A-page 31