PIC16F872-E/SS Microchip Technology, PIC16F872-E/SS Datasheet - Page 87

• Manufacturer Part Number: PIC16F872-E/SS
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,SSOP,28PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F872-E/SS

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 28-SSOP
• Package: 28SSOP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 22
• Interface Type: I2C/SPI
• On-chip Adc: 5-chx10-bit
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.5
1997 Microchip Technology Inc.
Arithmetic Logical Unit (ALU)
PICmicro MCUs contain an 8-bit ALU and an 8-bit working register. The ALU is a general pur-
pose arithmetic and logical unit. It performs arithmetic and Boolean functions between the data
in the working register and any register file.
Figure 5-3: Operation of the ALU and W Register
The ALU is 8-bits wide and is capable of addition, subtraction, shift and logical operations. Unless
otherwise mentioned, arithmetic operations are two's complement in nature. In two-operand
instructions, typically one operand is the working register (W register). The other operand is a file
register or an immediate constant. In single operand instructions, the operand is either the W reg-
ister or a file register.
The W register is an 8-bit working register used for ALU operations. It is not an addressable reg-
ister.
Depending on the instruction executed, the ALU may affect the values of the Carry (C), Digit
Carry (DC), and Zero (Z) bits in the STATUS register. The C and DC bits operate as a borrow bit
and a digit borrow out bit, respectively, in subtraction. See the SUBLW and SUBWF instructions for
examples.
Literal Instructions
d = '0' or
W Register
(from instruction word)
8
ALU
8-bit literal
8
Section 5. CPU and ALU
d bit, or from instruction
d = '1'
8
8
8
8-bit register value
(from direct or indirect
address of instruction)
Register
Registers
Function
Purpose
General
Special
(SFR’s)
(GPR)
File
RAM
and
DS31005A-page 5-5
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