Microchip Technology MA330028 Data Sheet
2011-2013 Microchip Technology Inc.
DS70000657H-page 379
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X AND PIC24EPXXXGP/MC20X
27.0
SPECIAL FEATURES
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X
and PIC24EPXXXGP/MC20X devices include several
features intended to maximize application flexibility and
reliability, and minimize cost through elimination of
external components. These are:
• Flexible Configuration
• Watchdog Timer (WDT)
• Code Protection and CodeGuard™ Security
• JTAG Boundary Scan Interface
• In-Circuit Serial Programming™ (ICSP™)
• In-Circuit Emulation
and PIC24EPXXXGP/MC20X devices include several
features intended to maximize application flexibility and
reliability, and minimize cost through elimination of
external components. These are:
• Flexible Configuration
• Watchdog Timer (WDT)
• Code Protection and CodeGuard™ Security
• JTAG Boundary Scan Interface
• In-Circuit Serial Programming™ (ICSP™)
• In-Circuit Emulation
27.1
Configuration Bits
In dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/
50X and PIC24EPXXXGP/MC20X devices, the
Configuration bytes are implemented as volatile mem-
ory. This means that configuration data must be
programmed each time the device is powered up.
Configuration data is stored in at the top of the on-chip
program memory space, known as the Flash Configura-
tion bytes. Their specific locations are shown in
50X and PIC24EPXXXGP/MC20X devices, the
Configuration bytes are implemented as volatile mem-
ory. This means that configuration data must be
programmed each time the device is powered up.
Configuration data is stored in at the top of the on-chip
program memory space, known as the Flash Configura-
tion bytes. Their specific locations are shown in
. The configuration data is automatically
loaded from the Flash Configuration bytes to the proper
Configuration Shadow registers during device Resets.
Configuration Shadow registers during device Resets.
When creating applications for these devices, users
should always specifically allocate the location of the
Flash Configuration bytes for configuration data in their
code for the compiler. This is to make certain that pro-
gram code is not stored in this address when the code
is compiled.
The upper 2 bytes of all Flash Configuration Words in
program memory should always be ‘1111 1111 1111
1111
should always specifically allocate the location of the
Flash Configuration bytes for configuration data in their
code for the compiler. This is to make certain that pro-
gram code is not stored in this address when the code
is compiled.
The upper 2 bytes of all Flash Configuration Words in
program memory should always be ‘1111 1111 1111
1111
’. This makes them appear to be NOP instructions
in the remote event that their locations are ever
executed by accident. Since Configuration bits are not
implemented in the corresponding locations, writing
‘1’s to these locations has no effect on device
operation.
executed by accident. Since Configuration bits are not
implemented in the corresponding locations, writing
‘1’s to these locations has no effect on device
operation.
The Configuration Flash bytes map is shown in
Note:
This data sheet summarizes the
features of the dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X and
PIC24EPXXXGP/MC20X families of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to the related section of the
“dsPIC33/PIC24 Family Reference
Manual
features of the dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X and
PIC24EPXXXGP/MC20X families of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to the related section of the
“dsPIC33/PIC24 Family Reference
Manual
”, which is available from the
www.microchip.com
).
Note:
Configuration data is reloaded on all types
of device Resets.
of device Resets.
Note:
Performing a page erase operation on the
last page of program memory clears the
Flash Configuration bytes, enabling code
protection as a result. Therefore, users
should avoid performing page erase
operations on the last page of program
memory.
last page of program memory clears the
Flash Configuration bytes, enabling code
protection as a result. Therefore, users
should avoid performing page erase
operations on the last page of program
memory.