PIC12F629T-E/MD MICROCHIP [Microchip Technology], PIC12F629T-E/MD Datasheet - Page 20

• Manufacturer Part Number: PIC12F629T-E/MD
• Description: 8-Pin, Flash-Based 8-Bit CMOS Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

PIC12F629/675
2.4
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 data pointed to by the File Select
Register (FSR). Reading INDF itself indirectly will
produce 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 2-2.
FIGURE 2-2:
DS41190G-page 20
Bank Select Location Select
RP1
For memory map detail see Figure 2-2.
Note 1: The RP1 and IRP bits are reserved; always maintain these bits clear.
(1)
Indirect Addressing, INDF and
FSR Registers
RP0
Direct Addressing
6
Data
Memory
DIRECT/INDIRECT ADDRESSING PIC12F629/675
From Opcode
7Fh
00h
Bank 0
00
0
Bank 1
01
Bank 2
10
Not Used
A simple program to clear RAM location 20h-2Fh using
indirect addressing is shown in Example 2-1.
EXAMPLE 2-1:
NEXT
CONTINUE
Bank 3
11
IRP
MOVLW
MOVWF
CLRF
INCF
BTFSS
GOTO
Bank Select
180h
(1)
1FFh
0x20
FSR
INDF
FSR
FSR,4
NEXT
7
Indirect Addressing
INDIRECT ADDRESSING
 2010 Microchip Technology Inc.
;initialize pointer
;to RAM
;clear INDF register
;inc pointer
;all done?
;no clear next
;yes continue
FSR Register
Location Select
0