PIC16C84_13 Datasheet, PDF (8/110 Pages) Microchip Technology – 8-bit CMOS EEPROM Microcontroller

PIC16C84
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.
FIGURE 3-1: PIC16C84 BLOCK DIAGRAM
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 PIC16C84 is shown
in Figure 3-1, its corresponding pin description is
shown in Table 3-1.
EEPROM
Program
Memory
1K x 14
13
Program Counter
8 Level Stack
(13-bit)
Data Bus 8
RAM
File Registers
36 x 8
EEPROM Data Memory
EEDATA
EEPROM
Data Memory
64 x 8
Program
Bus 14
Instruction reg
5 _{Direct Addr}
8
7
RAM Addr
Addr Mux
7 Indirect
Addr
FSR reg
STATUS reg
TMR0
EEADR
RA4/T0CKI
Instruction
Decode &
Control
Timing
Generation
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
MUX
ALU
W reg
I/O Ports
RA3:RA0
RB7:RB1
RB0/INT
OSC2/CLKOUT
OSC1/CLKIN
MCLR VDD, VSS
DS30445D-page 8
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