PIC12C671/JW Microchip Technology, PIC12C671/JW Datasheet - Page 106

• Manufacturer Part Number: PIC12C671/JW
• Description: IC MCU EPROM 1KX14 A/D 8CDIP
• Manufacturer: Microchip Technology
• Series: PIC® 12Cr

Specifications of PIC12C671/JW

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 10MHz
• Peripherals: POR, WDT
• Number Of I /o: 5
• Program Memory Size: 1.75KB (1K x 14)
• Program Memory Type: EPROM, UV
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 4x8b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 8-CDIP (0.300", 7.62mm) Window
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Connectivity: -

PICmicro MID-RANGE MCU FAMILY
6.3.4
DS31006A-page 6-12
Indirect Addressing, INDF, and FSR Registers
Indirect addressing is a mode of addressing data memory where the data memory address in
the instruction is not fixed. An SFR register is used as a pointer to the data memory location that
is to be read or written. Since this pointer is in RAM, the contents can be modified by the pro-
gram. This can be useful for data tables in the data memory.
indirect addressing. This shows the moving of the value to the data memory address specified
by the value of the FSR register.
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 reg-
ister 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 generated by
the concatenation of the IRP bit (STATUS<7>) with the 8-bit FSR register, as shown in
Figure 6-7: Indirect Addressing
Instruction
Executed
Instruction
Fetched
Opcode
Opcode
Address != 0
RP1:RP0
2
Address
File
9
7
9
Address = 0h
File Address = INDF
IRP
9
Figure 6-7
FSR
RAM
1997 Microchip Technology Inc.
shows the operation of
Figure
6-8.