PIC18F2480/2580/4480/4580
FIGURE 25-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Program Memory Configuration Bit Settings
Register Values
000000h
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
0007FFh
000800h
TBLPTR = 0008FFh
003FFFh
004000h
TBLRD*
PC = 007FFEh
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
007FFFh
008000h
00BFFFh
00C000h
WRT3, EBTR3 = 11
00FFFFh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 25-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
Program Memory
Configuration Bit Settings
000000h
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
0007FFh
000800h
TBLPTR = 0008FFh
PC = 003FFEh
TBLRD*
003FFFh
004000h
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
007FFFh
008000h
00BFFFh
00C000h
00FFFFh
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
© 2009 Microchip Technology Inc.
DS39637D-page 365
MICROCHIP [ MICROCHIP ]
