1. Introduction to PIC Microcontrollers
The PIC 16F84A

3. PIC Microcontrollers are quickly replacing computers when it comes to programming robotic devices. These microcontrollers are small and can be programmed to carry out a number of tasks and are ideal for school and industrial projects. A simple program is written using a computer, it is then downloaded to a microcontroller which in turn can control a robotic device.

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The PICmicro Family
Microchip is the company that develops and sells the PIC microcontroller
PICMicro devices are grouped by the size of their Instruction Word
The three current PICmicro families are:
Base-Line: 12-bit Instruction Word lengths
Mid-Range: 14-bit Instruction Word length
High-End: 16-bit Instruction Word length
This presentation focuses on the Mid-Range device:
The PIC16F84A
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5. Memory Type Designation
The memory type is designated in the part number by the first letter(s) after the family affiliation designators.
C, as in PIC16CXXX.
These devices have EPROM type memory.
CR, as in PIC16CRXXX
These devices have ROM type memory.
F, as in PIC16FXXX
These devices have Flash type memory.
Memory technology has no effect on the logical operation of a device
Due to the different processing steps required, some electrical characteristics may vary between devices with the same feature set/pinout but with different memory technologies
When discussing the functionality of the device, the memory technology and the voltage range do not matter
Microchip offers three program memory types
All Mid-Range PICmicro™ MCUs operate over the standard voltage range
Devices are also offered which operate over an extended voltage range (and reduced frequency range).
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6. Device Memory Type and Voltage Range Designators
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7. Different Types of Memory
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8. The 8-pin Enhanced FLASH/EEPROM 8-Bit Microcontroller
The PIC16F84A
The 8-pin Enhanced FLASH/EEPROM
8-Bit Microcontroller
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9. High Performance RISC CPU Features
Only 35 single word instructions to learn
All instructions single-cycle except for program branches which are two-cycle
Operating speed: DC - 20 MHz clock input
DC ns instruction cycle
1024 words of program memory
68 bytes of Data RAM
64 bytes of Data EEPROM
14-bit wide instruction words
8-bit wide data bytes
15 Special Function Hardware registers
Eight-level deep hardware stack
Direct, indirect and relative addressing modes
Four interrupt sources:
External RB0/INT pin
TMR0 timer overflow
PORTB<7:4> interrupt-on-change
Data EEPROM write complete
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10. Special Microcontroller Features
Peripheral Features:
13 I/O pins with individual direction control
High current sink/source for direct LED drive
25 mA sink max. per pin
25 mA source max. per pin
TMR0: 8-bit timer/counter with 8-bit programmable prescaler
Special Microcontroller Features
CMOS Enhanced FLASH/EEPROM Technology
10,000 erase/write cycles Enhanced FLASH Program memory typical
10,000,000 typical erase/write cycles
EEPROM Data memory typical EEPROM Data Retention > 40 years
In-Circuit Serial Programming™ (ICSP™) – via two pins
Power-on Reset (POR), Power-up Timer (PWRT), Oscillator Start-up Timer (OST)
Watchdog Timer (WDT) with its own On-Chip RC Oscillator for reliable operation
Code protection
Power saving SLEEP mode
Selectable oscillator options
Low power, high speed technology
Fully static design
Wide operating voltage range:
Commercial: 2.0V to 5.5V
Industrial: 2.0V to 5.5V
Low power consumption:
< 2 mA 5V, 4 MHz
15 mA 2V, 32 kHz
< 0.5 mA typical standby 2V
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The PIC16F84A
ARCHITECTURE
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PIC16F84A Block Diagram
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DEVICE OVERVIEW
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14. Pin Diagrams and Designations
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15. Oscillator Configurations
The PIC16F84A can be operated in four different oscillator modes
The user can program two configuration bits (FOSC1 and FOSC0) to select one of these four modes:
LP Low Power Crystal
XT Crystal/Resonator
HS High Speed Crystal/Resonator
RC Resistor/Capacitor
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16. PIC 16F84A DC Characteristics
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17. Absolute Maximum Ratings
Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
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