Microchip Technology ARD00385 Data Sheet
2009-2011 Microchip Technology Inc.
DS39957D-page 449
PIC18F87K90 FAMILY
FIGURE 28-8:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
FIGURE 28-9:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
TBLRD*
TBLPTR = 0008FFh
PC = 007FFEh
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
0007FFh
000800h
000800h
003FFFh
004000h
004000h
007FFFh
008000h
00BFFFh
00C000h
00FFFFh
WRTB, EBTRB = 11
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
WRT2, EBTR2 = 11
WRT3, EBTR3 = 11
TBLRD*
TBLPTR = 0008FFh
PC = 003FFEh
Register Values
Program Memory
Configuration Bit Settings
Results:
Table reads are permitted within Blockn, even when EBTRBn = 0.
The TABLAT register returns the value of the data at the location, TBLPTR.
000000h
0007FFh
000800h
000800h
003FFFh
004000h
004000h
007FFFh
008000h
00BFFFh
00C000h
00FFFFh