DSPIC33FJ64GP306 Microchip Technology Inc., DSPIC33FJ64GP306 Datasheet - Page 33

• Manufacturer Part Number: DSPIC33FJ64GP306
• 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
Program Memory
PROGRAM MEMORY ORGANIZATION
‘Phantom’ Byte
(read as ‘0’)
00000000
00000000
00000000
00000000
space
most significant word
is
dsPIC33FJXXXGPX06/X08/X10
23
organized
in
16
Instruction Width
3.1.2
All dsPIC33FJXXXGPX06/X08/X10 devices reserve
the addresses between 0x00000 and 0x000200 for
hard-coded program execution 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.
dsPIC33FJXXXGPX06/X08/X10 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 discussion of the interrupt vec-
tor 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
DS70286A-page 31