PIC18F4321 Datasheet, PDF (272/396 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F4321 FAMILY
FIGURE 23-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Register Values
Program Memory⁽¹⁾ Configuration Bit Settings
Boot Block
WRTB, EBTRB = 11
TBLPTR = 0008FFh
Block 0
WRT0, EBTR0 = 10
PC = 007FFEh
Block 1
TBLRD*
WRT1, EBTR1 = 11
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
Note 1: See Figure 23-5 for block boundaries.
FIGURE 23-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
Program Memory⁽¹⁾
Configuration Bit Settings
Boot Block
WRTB, EBTRB = 11
TBLPTR = 0008FFh
PC = 003FFEh
Block 0
TBLRD*
Block 1
WRT0, EBTR0 = 10
WRT1, EBTR1 = 11
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
Note 1: See Figure 23-5 for block boundaries.
DS39689E-page 270
Preliminary
© 2007 Microchip Technology Inc.