PIC18F23K20-E/MLQTP MICROCHIP [Microchip Technology], PIC18F23K20-E/MLQTP Datasheet - Page 93

• Manufacturer Part Number: PIC18F23K20-E/MLQTP
• Description: 28/40/44-Pin Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

6.3
The TBLRD instruction retrieves 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
Reading the Flash Program
Memory
Instruction Register
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
TBLRD*+
MOVF
MOVWF
TBLRD*+
MOVFW
MOVF
(IR)
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
Advance Information
Program Memory
; Load TBLPTR with the base
; address of the word
; read into TABLAT and increment
; get data
; read into TABLAT and increment
; get data
(Odd Byte Address)
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.
PIC18F2XK20/4XK20
TBLPTR = xxxxx1
TBLRD
Read Register
TABLAT
TBLPTR = xxxxx0
DS41303B-page 91