23-04-2012, 12:09 PM
Flash Memory Programming Specification
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PROGRAMMING THE PIC16F87XA
The PIC16F87XA is programmed using a serial
method. The Serial mode will allow the PIC16F87XA to
be programmed while in the user’s system. This allows
for increased design flexibility. This programming specification
applies to PIC16F87XA devices in all
packages.
PROGRAM MODE ENTRY User Program Memory Map
The user memory space extends from 0000h to 1FFFh
(8 K words). In Programming mode, the program memory
space extends from 0000h to 3FFFh, with the first
half (0000h - 1FFFh) being user program memory and
the second half (2000h - 3FFFh) being configuration
memory. The PC will increment from 0000h to 1FFFh
and wrap around to 0000h. From 2000h, the PC will
increment up to 3FFFh and wrap around to 2000h (not
to 0000h). Once in configuration memory, the highest
bit of the PC stays a ‘1’, thus always pointing to the configuration
memory. The only way to point to user program
memory is to reset the part and re-enter
Program/Verify mode, as described in Section 2.4.
ID Locations
A user may store identification information (ID) in four
ID locations. The ID locations are mapped in addresses
2000h - 2003h. It is recommended that the user use
only the four Least Significant bits of each ID location.
In some devices, the ID locations read out in an
unscrambled fashion after code protection is enabled.