PIC16LC926-SCL View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16LC926-SCL

64/68-Pin CMOS Microcontrollers with LCD Driver

Microchip Technology 

PIC16C925/926

2.6 Indirect Addressing, INDF and

FSR Registers

The INDF register is not a physical register. Addressing

the INDF register will cause indirect addressing.

Indirect addressing is possible by using the INDF reg-

ister. Any instruction using the INDF register actually

accesses the register pointed to by the File Select Reg-

ister (FSR). Reading the INDF register itself, indirectly

(FSR = ’0’), will produce 00h. Writing to the INDF regis-

ter indirectly results in a no operation (although status

bits may be affected). An effective 9-bit address is

obtained by concatenating the 8-bit FSR register and

the IRP bit (STATUS<7>), as shown in Figure 2-6.

A simple program to clear RAM locations 20h-2Fh

using indirect addressing is shown in Example 2-2.

EXAMPLE 2-2: INDIRECT ADDRESSING

MOVLW 0x20

MOVWF FSR

NEXT

CLRF INDF

INCF FSR,F

BTFSS FSR,4

GOTO NEXT

CONTINUE

;initialize pointer

;to RAM

;clear INDF register

;inc pointer

;all done?

;no clear next

:

;yes continue

FIGURE 2-6:

DIRECT/INDIRECT ADDRESSING

Direct Addressing

RP1:RP0 6

From Opcode 0

Indirect Addressing

IRP

7

FSR Register

0

Bank Select Location Select

Bank Select

00

01

10

11

00h

00h

Location Select

Data

Memory

7Fh

Bank 0

Bank 1 Bank 2

7Fh

Bank 3

Note: For memory map detail, see Figure 2-3.

DS39544A-page 26

Preliminary

 2001 Microchip Technology Inc.

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