PIC18F2450 Datasheet, PDF (210/320 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 (EBTRn) 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 EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 18-8:
EXTERNAL BLOCK TABLE READ (EBTRn) 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 EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
DS39760A-page 208
Advance Information
© 2006 Microchip Technology Inc.