PIC18F6520-I Datasheet, PDF (258/380 Pages) Micrel Semiconductor – 64/80-Pin High-Performance, 256 Kbit to 1 Mbit Enhanced Flash Microcontrollers with A/D

PIC18F6520/8520/6620/8620/6720/8720
FIGURE 23-6:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Register Values
TBLPTR = 000FFFh
PC = 004FFEh
Program Memory
000000h
0001FFh
000200h
TBLRD *
003FFFh
004000h
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
007FFFh
008000h
WRT2, EBTR2 = 11
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: All table reads from external blocks to Block n are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
TBLPTR = 000FFFh
PC = 003FFEh
Program Memory
000000h
0001FFh
000200h
TBLRD *
003FFFh
004000h
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
007FFFh
008000h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: Table reads permitted within Block n, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
DS39609B-page 256
 2004 Microchip Technology Inc.