PIC18F2450_08 Datasheet, PDF (212/324 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2450/4450
FIGURE 18-7:
EXTERNAL BLOCK TABLE READ (EBTRx) DISALLOWED
Register Values
TBLPTR = 0008FFh
PC = 003FFEh
Program Memory
000000h
0007FFh
000FFFh
001000h
TBLRD*
001FFFh
002000h
003FFFh
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
Results: All table reads from external blocks to Blockn are disabled whenever EBTRx = 0.
TABLAT register returns a value of ‘0’.
FIGURE 18-8:
EXTERNAL BLOCK TABLE READ (EBTRx) ALLOWED
Register Values
TBLPTR = 0008FFh
PC = 001FFEh
Program Memory
000000h
0007FFh
000FFFh
001000h
TBLRD*
001FFFh
002000h
003FFFh
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
Results: Table reads permitted within Blockn, even when EBTRBx = 0.
TABLAT register returns the value of the data at the location TBLPTR.
DS39760D-page 210
© 2008 Microchip Technology Inc.