16F84A Microchip Technology, 16F84A Datasheet - Page 3

• Manufacturer Part Number: 16F84A
• Description: 18-pin Enhanced Flash/EEPROM 8-Bit Microcontroller
• Manufacturer: Microchip Technology

1.0
This document contains device-specific information for
the operation of the PIC16F84A device. Additional
information may be found in the PICmicro™ Mid-Range
Reference Manual, (DS33023), which may be down-
loaded from the Microchip website. The Reference
Manual should be considered a complementary docu-
ment to this data sheet, and is highly recommended
reading for a better understanding of the device archi-
tecture and operation of the peripheral modules.
The PIC16F84A belongs to the mid-range family of the
PICmicro™ microcontroller devices. A block diagram of
the device is shown in Figure 1-1.
FIGURE 1-1:
1998 Microchip Technology Inc.
Program
PIC16F84A
OSC2/CLKOUT
Bus
DEVICE OVERVIEW
OSC1/CLKIN
Program
Memory
1K x 14
Instruction reg
Flash
Generation
Instruction
Decode &
Control
Timing
14
PIC16F84A BLOCK DIAGRAM
13
MCLR
5
Start-up Timer
Program Counter
Power-on
Watchdog
Power-up
Oscillator
8 Level Stack
Reset
Timer
Timer
(13-bit)
Direct Addr
V
DD
8
, V
SS
Preliminary
File Registers
PIC16F84A
Addr Mux
W reg
ALU
Data Bus
68 x 8
RAM
7
STATUS reg
The program memory contains 1K words, which trans-
lates to 1024 instructions, since each 14-bit program
memory word is the same width as each device instruc-
tion. The data memory (RAM) contains 68 bytes. Data
EEPROM is 64 bytes.
There are also 13 I/O pins that are user-configured on
a pin-to-pin basis. Some pins are multiplexed with other
device functions. These functions include:
• External interrupt
• Change on PORTB interrupt
• Timer0 clock input
Table 1-1 details the pinout of the device with descrip-
tions and details for each pin.
FSR reg
MUX
7
RAM Addr
Indirect
Addr
8
8
EEPROM Data Memory
EEDATA
I/O Ports
PIC16F84A
TMR0
DS35007A-page 3
Data Memory
EEPROM
EEADR
RA4/T0CKI
64 x 8
RB7:RB1
RA3:RA0
RB0/INT