Datasheet

 2010 Microchip Technology Inc. DS39616D-page 281
PIC18F2331/2431/4331/4431
FIGURE 23-7: EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
FIGURE 23-8: EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
000000h
0001FFh
000200h
0007FFh
000800h
000FFFh
001000h
0017FFh
001800h
001FFFh
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
TBLRD *
TBLPTR = 0002FFh
PC = 000FFEh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
The TABLAT register returns a value of ‘0’.
Register Values
Program Memory
Configuration Bit Settings
000000h
0001FFh
000200h
0007FFh
000800h
000FFFh
001000h
0017FFh
001800h
001FFFh
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
TBLRD *
TBLPTR = 0002FFh
PC = 0007FEh
Register Values
Program Memory
Configuration Bit Settings
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
The TABLAT register returns the value of the data at the location TBLPTR.