Datasheet

PIC16F8X
DS30430D-page 8  1996-2013 Microchip Technology Inc.
PIC16CXX devices contain an 8-bit ALU and working
register. The ALU is a general purpose arithmetic unit.
It performs arithmetic and Boolean functions between
data in the working register and any register file.
The ALU is 8-bits wide and 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), and the other operand is a file register or
an immediate constant. In single operand instructions,
the operand is either the W register or a file register.
The W register is an 8-bit working register used for ALU
operations. It is not an addressable register.
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
and digit borrow out bit,
respectively, in subtraction. See the SUBLW and SUBWF
instructions for examples.
A simplified block diagram for the PIC16F8X is shown
in Figure 3-1, its corresponding pin description is
shown in Table 3-1.
FIGURE 3-1: PIC16F8X BLOCK DIAGRAM
Flash/ROM
Program
Memory
Program Counter
13
Program
Bus
Instruction reg
8 Level Stack
(13-bit)
Direct Addr
8
Instruction
Decode &
Control
Timing
Generation
OSC2/CLKOUT
OSC1/CLKIN
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
MCLR
VDD, VSS
W reg
ALU
MUX
I/O Ports
TMR0
STATUS reg
FSR reg
Indirect
Addr
RA3:RA0
RB7:RB1
RA4/T0CKI
EEADR
EEPROM
Data Memory
64 x 8
EEDATA
Addr Mux
RAM Addr
RAM
File Registers
EEPROM Data Memory
Data Bus
5
7
7
PIC16F84/CR84
1K x 14
PIC16F83/CR83
512 x 14
PIC16F83/CR83
36 x 8
PIC16F84/CR84
68 x 8
RB0/INT
14
8
8