PIC18F2682-I/PT MICROCHIP [Microchip Technology], PIC18F2682-I/PT Datasheet - Page 101

• Manufacturer Part Number: PIC18F2682-I/PT
• Description: 28/40/44-Pin Enhanced Flash Microcontrollers with ECAN Technology, 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

6.3
The TBLRD instruction is used to retrieve data from
program memory and places it into data RAM. Table
reads from program memory are performed one byte at
a time.
TBLPTR points to a byte address in program space.
Executing TBLRD places the byte pointed to into
TABLAT. In addition, TBLPTR can be modified
automatically for the next table read operation.
FIGURE 6-4:
EXAMPLE 6-1:
© 2007 Microchip Technology Inc.
READ_WORD
Instruction Register
Reading the Flash Program
Memory
(IR)
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
TBLRD*+
MOVF
MOVWF
TBLRD*+
MOVF
MOVF
READS FROM FLASH PROGRAM MEMORY
READING A FLASH PROGRAM MEMORY WORD
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
TABLAT, W
WORD_EVEN
TABLAT, W
WORD_ODD
(Even Byte Address)
FETCH
Program Memory
PIC18F2682/2685/4682/4685
Preliminary
(Odd Byte Address)
; Load TBLPTR with the base
; address of the word
; read into TABLAT and increment
; get data
; read into TABLAT and increment
; get data
The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word. Figure 6-4
shows the interface between the internal program
memory and the TABLAT.
TBLRD
TBLPTR = xxxxx1
Read Register
TABLAT
TBLPTR = xxxxx0
DS39761B-page 99