PIC18F2525_08 Datasheet, PDF (267/412 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F2525/2620/4525/4620
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRx) DISALLOWED
Register Values
Program Memory
Configuration Bit Settings
TBLPTR = 0008FFh
000000h
0007FFh
000800h
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
PC = 007FFEh
TBLRD*
003FFFh
004000h
007FFFh
008000h
00BFFFh
00C000h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
00FFFFh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRx = 0.
TABLAT register returns a value of ‘0’.
FIGURE 23-8:
EXTERNAL BLOCK TABLE READ (EBTRx) ALLOWED
Register Values
TBLPTR = 0008FFh
Program Memory
000000h
0007FFh
000800h
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
PC = 003FFEh
TBLRD*
003FFFh
004000h
007FFFh
008000h
00BFFFh
00C000h
00FFFFh
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
Results: Table reads permitted within Blockn, even when EBTRx = 0.
TABLAT register returns the value of the data at the location TBLPTR.
© 2008 Microchip Technology Inc.
DS39626E-page 265