PIC10F222 Microchip Technology Inc., PIC10F222 Datasheet - Page 22

• Manufacturer Part Number: PIC10F222
• Description: High-performance Microcontrollers With 8-bit A/d
• Manufacturer: Microchip Technology Inc.

PIC10F220/222
4.9
The INDF register is not a physical register. Addressing
INDF actually addresses the register whose address is
contained in the FSR register (FSR is a pointer). This is
indirect addressing.
4.9.1
• Register file 09 contains the value 10h
• Register file 0A contains the value 0Ah
• Load the value 09 into the FSR register
• A read of the INDF register will return the value
• Increment the value of the FSR register by one
• A read of the INDR register now will return the
Reading INDF itself indirectly (FSR = 0) will produce
00h. Writing to the INDF register indirectly results in a
no-operation (although Status bits may be affected).
A simple program to clear RAM locations 10h-1Fh
using Indirect addressing is shown in Example 4-1.
FIGURE 4-6:
DS41270E-page 20
of 10h
(FSR = 0A)
value of 0Ah.
Note 1: For register map detail, see Section 4.3 “Data Memory Organization”.
Indirect Data Addressing; INDF
and FSR Registers
INDIRECT ADDRESSING
DIRECT/INDIRECT ADDRESSING
Location Select
Data
Memory
Direct Addressing
4
(opcode)
(1)
1Fh
00h
0Fh
10h
0
Bank 0
EXAMPLE 4-1:
The FSR is a 5-bit wide register. It is used in conjunc-
tion with the INDF register to indirectly address the data
memory area.
The FSR<4:0> bits are used to select data memory
addresses 00h to 1Fh.
NEXT
CONTINUE
Note:
MOVLW
MOVWF
CLRF
INCF
BTFSC
GOTO
Do not use banking. FSR <7:5> are
unimplemented and read as ‘1’s.
Indirect Addressing
:
:
4
0x10
FSR
INDF
FSR,F
FSR,4
NEXT
Location Select
(FSR)
HOW TO CLEAR RAM
USING INDIRECT
ADDRESSING
© 2007 Microchip Technology Inc.
;initialize pointer
;to RAM
;clear INDF
;register
;inc pointer
;all done?
;NO, clear next
;YES, continue
0