PIC16F767T-I/ML View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16F767T-I/ML

28/40/44-Pin, 8-Bit CMOS Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

Microchip Technology 

PIC16F7X7

2.5 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

register. Any instruction using the INDF register

actually accesses the register pointed to by the File

Select Register, FSR. Reading the INDF register itself

indirectly (FSR = 0) will read 00h. Writing to the INDF

register 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 2-5.

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

using indirect addressing is shown in Example 2-2.

EXAMPLE 2-2: INDIRECT ADDRESSING

MOVLW

MOVWF

NEXT CLRF

INCF

BTFSS

GOTO

CONTINUE

:

0x20

FSR

INDF

FSR, F

FSR, 4

NEXT

;initialize pointer

;to RAM

;clear INDF register

;inc pointer

;all done?

;no clear next

;yes continue

FIGURE 2-5:

DIRECT/INDIRECT ADDRESSING

Direct Addressing

RP1:RP0 6

From Opcode 0

Indirect Addressing

IRP

7

FSR Register

0

Bank Select Location Select

00

00h

01

80h

10

100h

11

180h

Bank Select

Location Select

Data

Memory(1)

7Fh

FFh

17Fh

1FFh

Bank 0 Bank 1 Bank 2 Bank 3

Note 1: For register file map detail, see Figure 2-2.

DS30498C-page 30

 2004 Microchip Technology Inc.

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