PIC16F MICROCHIP [Microchip Technology], PIC16F Datasheet - Page 31

• Manufacturer Part Number: PIC16F
• Description: PIC16F/LF182X/PIC12F/LF1822 Memory Programming Specification
• Manufacturer: MICROCHIP [Microchip Technology]

7.4.2
With the program code protection enabled, the
checksum is computed in the following manner: The
Least Significant nibble of each User ID is used to
create a 16-bit value. The masked value of User ID
EXAMPLE 7-3:
EXAMPLE 7-4:
 2010 Microchip Technology Inc.
PIC16F1827
PIC16LF1827
PROGRAM CODE PROTECTION
ENABLED
Configuration Word 2 mask
User ID (8000h)
User ID (8001h)
User ID (8002h)
User ID (8003h)
Sum of User IDs = (0006h and 000Fh) << 12 + (0007h and 000Fh) << 8 +
Configuration Word 1
Configuration Word 1 mask
Configuration Word 2
Checksum
Checksum
Sum of User IDs
Configuration Word 1
Configuration Word 1 mask
Configuration Word 2
Configuration Word 2 mask
User ID (8000h)
User ID (8001h)
User ID (8002h)
User ID (8003h)
CHECKSUM COMPUTED WITH PROGRAM CODE PROTECTION ENABLED
PIC16F1827, BLANK DEVICE
CHECKSUM COMPUTED WITH PROGRAM CODE PROTECTION ENABLED
PIC16LF1827, 00AAh AT FIRST AND LAST ADDRESS
PIC16F/LF182X/PIC12F/LF1822
= (3F7Fh and 3FFFh) + (3FFFh and 3713h) + Sum of User IDs
= 6000h + 0700h + 0010h + 0002h
= 6712h
= DDA4h
= 3F7Fh +3713h + 6712h
= (3F7Fh and 3FFFh) + (3FFFh and 3703h) + Sum of User IDs
= 5EDAh
(0001h and 000Fh) << 4 + (0002h and 000Fh)
= E000h + 0800h + 0050h + 0008h
= E858h
= 3F7Fh +3703h + E858h
= (000Eh and 000Fh) << 12 + (0008h and 000Fh) << 8 +
Advance Information
(0005h and 000Fh) << 4 + (0008h and 000Fh)
location 8000h is the Most Significant nibble. This Sum
of User IDs is summed with the Configuration Words
(all unimplemented Configuration bits are masked to
‘0’).
Note:
3F7Fh
3FFFh
3FFFh
3713h
0006h
0007h
0001h
0002h
000Eh
0008h
0005h
0008h
3F7Fh
3FFFh
3FFFh
3703h
Data
checksum.
memory
does
DS41390C-page 31
not
effect
the