PIC16F873A-I/SS Microchip Technology, PIC16F873A-I/SS Datasheet - Page 106

• Manufacturer Part Number: PIC16F873A-I/SS
• Description: IC MCU FLASH 4KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F873A-I/SS

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 128Byte
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Core: PIC
• Processor Series: PIC16F
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Data Ram Size: 192 B
• Data Rom Size: 128 B
• On-chip Adc: Yes
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 5
• Height: 1.75 mm
• Interface Type: I2C, SPI, USART
• Length: 10.2 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Width: 5.3 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details
• Other names: PIC16F873AI/SS

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.