PIC18F2220/2320/4220/4320
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Program Memory Configuration Bit Settings
Register Values
000000h
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
0001FFh
000200h
TBLPTR = 0002FFh
0007FFh
000800h
TBLRD *
PC = 000FFEh
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
000FFFh
001000h
0017FFh
001800h
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
Configuration Bit Settings
000000h
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
0001FFh
000200h
TBLPTR = 0002FFh
PC = 0007FEh
TBLRD *
0007FFh
000800h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
000FFFh
001000h
0017FFh
001800h
001FFFh
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
2003 Microchip Technology Inc.
DS39599C-page 253
MICROCHIP [ MICROCHIP ]
