Microchip Technology MA330024 Data Sheet
dsPIC33FJ32GS406/606/608/610 and dsPIC33FJ64GS406/606/608/610
DS7000591F-page 46
2009-2014 Microchip Technology Inc.
4.1.1
PROGRAM MEMORY
ORGANIZATION
ORGANIZATION
The program memory space is organized in 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 (see
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 (see
Program memory addresses are always word-aligned
on the lower word and addresses are incremented or
decremented by two during the code execution. This
arrangement provides compatibility with data memory
space addressing and makes data in the program
memory space accessible.
on the lower word and addresses are incremented or
decremented by two during the code execution. This
arrangement provides compatibility with data memory
space addressing and makes data in the program
memory space accessible.
4.1.2
INTERRUPT AND TRAP VECTORS
All dsPIC33FJ32GS406/606/608/610 and
dsPIC33FJ64GS406/606/608/610 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 application at 0x000000, with the actual address
for the start of code at 0x000002.
dsPIC33FJ64GS406/606/608/610 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 application at 0x000000, with the actual address
for the start of code at 0x000002.
The dsPIC33FJ32GS406/606/608/610 and
dsPIC33FJ64GS406/606/608/610 devices also have
two Interrupt Vector Tables (IVT), 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”.
dsPIC33FJ64GS406/606/608/610 devices also have
two Interrupt Vector Tables (IVT), 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”.
FIGURE 4-2:
PROGRAM MEMORY ORGANIZATION
0
8
16
PC Address
0x000000
0x000002
0x000004
0x000006
0x000006
23
00000000
00000000
00000000
00000000
Program Memory
‘Phantom’ Byte
(read as ‘0’)
least significant word
most significant word
Instruction Width
0x000001
0x000003
0x000005
0x000007
0x000007
msw
Address
(lsw Address)