dspic33fj128mc204 Microchip Technology Inc., dspic33fj128mc204 Datasheet - Page 39

• Manufacturer Part Number: dspic33fj128mc204
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

4.1.1
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 4-2).
Program memory addresses are always word-aligned
on the lower word, and addresses are incremented or
decremented by two during code execution. This
arrangement provides compatibility with data memory
space addressing and makes data in the program
memory space accessible.
4.1.2
All
dsPIC33FJ64MCX02/X04,
dsPIC33FJ128MCX02/X04
FIGURE 4-2:
© 2009 Microchip Technology Inc.
program
0x000001
0x000003
0x000005
0x000007
Address
msw
PROGRAM MEMORY
ORGANIZATION
INTERRUPT AND TRAP VECTORS
memory
Program Memory
PROGRAM MEMORY ORGANIZATION
‘Phantom’ Byte
(read as ‘0’)
00000000
00000000
00000000
00000000
space
dsPIC33FJ32MC302/304,
most significant word
devices
is
23
organized
reserve
and
Preliminary
the
in
16
Instruction Width
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 application at 0x000000, with the actual
address for the start of code at 0x000002.
dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/X04,
and dsPIC33FJ128MCX02/X04 devices also have two
interrupt vector tables, located from 0x000004 to
0x0000FF and 0x000100 to 0x0001FF. These vector
tables allow each of the device interrupt sources to be
handled by separate Interrupt Service Routines (ISRs).
A more detailed discussion of the interrupt vector
tables is provided in Section 7.1 “Interrupt Vector
Table”.
least significant word
8
0
(lsw Address)
PC Address
0x000000
0x000002
0x000004
0x000006
DS70291C-page 37