SE9 datasheet(23/478 Pages) MICROCHIP

Numer części	SE9

Szczegółowy opis	64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt XLP Technology

PDF	478 Pages

Scroll/Zoom	100%

Producent	MICROCHIP [Microchip Technology]

Strona internetowa	http://www.microchip.com

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 2010-2012 Microchip Technology Inc.

DS41414D-page 23

PIC16(L)F1946/1947

3.1.1

READING PROGRAM MEMORY AS

DATA

There are two methods of accessing constants in pro-

gram memory. The first method is to use tables of

RETLW instructions. The second method is to set an

FSR to point to the program memory.

3.1.1.1

RETLW Instruction

The RETLW instruction can be used to provide access

to tables of constants. The recommended way to create

such a table is shown in Example 3-1.

EXAMPLE 3-1:

RETLW INSTRUCTION

The BRW instruction makes this type of table very

simple to implement. If your code must remain portable

with previous generations of microcontrollers, then the

BRW instruction is not available so the older table read

method must be used.

constants

BRW

;Add Index in W to

;program counter to

;select data

RETLW DATA0

;Index0 data

RETLW DATA1

;Index1 data

RETLW DATA2

RETLW DATA3

my_function

;… LOTS OF CODE…

MOVLW

DATA_INDEX

CALL constants

;… THE CONSTANT IS IN W

SE9 Arkusz danych(PDF) 23 Page - Microchip Technology