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PIC18F65K80T-I/SS View Datasheet(PDF) - Microchip Technology

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PIC18F65K80T-I/SS Datasheet PDF : 623 Pages
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PIC18F66K80 FAMILY
TABLE 28-4: SUMMARY OF CODE PROTECTION REGISTERS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
300008h CONFIG5L —
CP3
300009h CONFIG5H CPD
CPB
30000Ah CONFIG6L —
WRT3
30000Bh CONFIG6H WRTD WRTB WRTC
30000Ch CONFIG7L —
EBTR3
30000Dh CONFIG7H —
EBTRB
Legend: Shaded cells are unimplemented.
Bit 2
CP2
WRT2
EBTR2
Bit 1
CP1
WRT1
EBTR1
Bit 0
CP0
WRT0
EBTR0
28.6.1
PROGRAM MEMORY
CODE PROTECTION
The program memory may be read to, or written from,
any location using the table read and table write
instructions. The Device ID may be read with table
reads. The Configuration registers may be read and
written with the table read and table write instructions.
In normal execution mode, the CPx bits have no direct
effect. CPx bits inhibit external reads and writes. A block
of user memory may be protected from table writes if the
WRTx Configuration bit is ‘0’.
The EBTRx bits control table reads. For a block of
user memory with the EBTRx bit set to ‘0’, a table
read instruction that executes from within that block
is allowed to read. A table read instruction that exe-
cutes from a location outside of that block is not
allowed to read and will result in reading ‘0’s.
Figure 28-7 throughFigure 28-9 illustrate table write
and table read protection.
Note:
Code protection bits may only be written
to a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code
protection bits are only set to ‘1’ by a full
chip erase or block erase function. The full
chip erase and block erase functions can
only be initiated via ICSP or an external
programmer. Refer to the device
programming specification for more
information.
FIGURE 28-7:
TABLE WRITE (WRTx) DISALLOWED
Register Values
Program Memory
000000h
0007FFh
000800h
TBLPTR = 0008FFh
PC = 003FFEh
PC = 00BFFEh
TBLWT*
TBLWT*
003FFFh
004000h
007FFFh
008000h
00BFFFh
00C000h
00FFFFh
Results: All table writes are disabled to Blockn whenever WRTx = 0.
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 01
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
DS39977F-page 480
2010-2012 Microchip Technology Inc.

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