Datasheet

© 2009 Microchip Technology Inc. DS70286C-page 237
dsPIC33FJXXXGPX06/X08/X10
22.0 SPECIAL FEATURES
dsPIC33FJXXXGPX06/X08/X10 devices include
several features intended to maximize application
flexibility and reliability, and minimize cost through elim-
ination 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
22.1 Configuration Bits
The Configuration bits can be programmed (read as
‘0’), or left unprogrammed (read as ‘1’), to select
various device configurations. These bits are mapped
starting at program memory location 0xF80000.
The device Configuration register map is shown in
Table 22-1.
The individual Configuration bit descriptions for the
FBS, FSS, FGS, FOSCSEL, FOSC, FWDT, FPOR and
FICD Configuration registers are shown in Table 22-2.
Note that address 0xF80000 is beyond the user program
memory space. In fact, it belongs to the configuration
memory space (0x800000-0xFFFFFF) which can only be
accessed using table reads and table writes.
The upper byte of all device Configuration registers
should always be ‘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.
To prevent inadvertent configuration changes during
code execution, all programmable Configuration bits
are write-once. After a bit is initially programmed during
a power cycle, it cannot be written to again. Changing
a device configuration requires that power to the device
be cycled.
TABLE 22-1: DEVICE CONFIGURATION REGISTER MAP
Note: This data sheet summarizes the features
of the dsPIC33FJXXXGPX06/X08/X10
family of devices. However, it is not
intended to be a comprehensive reference
source. To complement the information in
this data sheet, refer to Section 23.
“CodeGuard™ Security” (DS70199),
Section 24. “Programming and
Diagnostics” (DS70207), and Section
25. “Device Configuration” (DS70194)
in the “dsPIC33F Family Reference
Manual”, which is available from the
Microchip web site (www.microchip.com).
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0xF80000 FBS RBS<1:0> — — BSS<2:0> BWRP
0xF80002 FSS RSS<1:0>
— — SSS<2:0> SWRP
0xF80004 FGS — — — — — GSS1 GSS0 GWRP
0xF80006 FOSCSEL IESO Reserved
(2)
— — —FNOSC<2:0>
0xF80008 FOSC FCKSM<1:0>
— — — OSCIOFNC POSCMD<1:0>
0xF8000A FWDT FWDTEN WINDIS
— WDTPRE WDTPOST<3:0>
0xF8000C FPOR
— — — — —FPWRT<2:0>
0xF8000E FICD Reserved
(1)
JTAGEN — — —ICS<1:0>
0xF80010 FUID0 User Unit ID Byte 0
0xF80012 FUID1 User Unit ID Byte 1
0xF80014 FUID2 User Unit ID Byte 2
0xF80016 FUID3 User Unit ID Byte 3
Note 1: When read, these bits will appear as ‘1’. When you write to these bits, set these bits to ‘1’.
2: When read, this bit returns the current programmed value.