PIC18F2220_07 Datasheet, PDF (255/386 Pages) Microchip Technology – 28/40/44-Pin High-Performance, Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F2220/2320/4220/4320
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Register Values
TBLPTR = 0002FFh
Program Memory
000000h
0001FFh
000200h
Configuration Bit Settings
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
PC = 000FFEh
TBLRD *
0007FFh
000800h
000FFFh
001000h
0017FFh
001800h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
001FFFh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 23-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
Program Memory
000000h
0001FFh
000200h
Configuration Bit Settings
WRTB, EBTRB = 11
TBLPTR = 0002FFh
WRT0, EBTR0 = 10
PC = 0007FEh
TBLRD *
0007FFh
000800h
000FFFh
001000h
0017FFh
001800h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
001FFFh
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
© 2007 Microchip Technology Inc.
DS39599F-page 253