Microchip PIC16F84A-04/SO 8-bit Microcontroller Data Sheet and Design Guide
The PIC16F84A-04/SO stands as a hallmark in the world of 8-bit microcontrollers, representing a robust and highly reliable solution for a vast array of embedded control applications. This comprehensive data sheet and design guide provides engineers with the critical information required to harness the full potential of this enduring component.
Housed in a compact 18-pin SOIC (SO) package, the device is designed for space-constrained applications. Its core is a high-performance RISC CPU featuring only 35 single-word instructions, all of which execute in a single cycle except for program branches, which take two. This architectural efficiency allows for incredibly fast operation, with the `-04` suffix denoting its capability to run at a maximum clock frequency of 4 MHz, achieving a single instruction cycle time of 1 µs.
A key feature of the PIC16F84A is its 1K x 14 words of EEPROM Program Memory and 68 bytes of RAM Data Memory. However, its most revolutionary feature for its time was the inclusion of 64 bytes of EEPROM Data Memory. This non-volatile memory can be written to electrically during operation, allowing for the storage of critical calibration data, user settings, or event logs that must be retained even after a power loss, all without the need for an external memory chip.
The I/O ports are highly versatile. The device offers 13 I/O pins distributed across Port A and Port B. Each pin is individually configurable as an input or output and can sink or source sufficient current to drive LEDs or other peripherals directly, simplifying circuit design. A critical timing peripheral is the 8-bit timer/counter with an 8-bit programmable prescaler, essential for creating precise delays or measuring time intervals.
The design guide portion of the documentation is indispensable for a successful implementation. It meticulously details:
Oscillator Configurations: Guidance on selecting and connecting crystal, RC, or external clock sources to the OSC1/OSC2 pins.
Reset Circuitry: The importance of a stable MCLR (Master Clear) pin connection for reliable power-on reset and manual reset functionality.
In-Circuit Serial Programming (ICSP): The protocol for programming the microcontroller after it has been soldered onto a PCB, using the dedicated RB6 and RB7 pins.
Interrupt Handling: Managing the external RB0/INT pin interrupt and the Timer0 overflow interrupt, which are crucial for responsive event-driven programming.
Power Management: Strategies for minimizing power consumption through the SLEEP mode, a critical consideration for battery-operated devices.
EEPROM Data Memory Handling: Precise procedures for reading from and writing to the internal EEPROM, including necessary delay considerations to ensure data integrity.
In summary, the data sheet for the PIC16F84A-04/SO is more than just a list of specifications; it is a complete design manual. It empowers engineers to create efficient, reliable, and cost-effective embedded systems, from industrial controls and automotive systems to security access devices and consumer electronics.
ICGOODFIND: The PIC16F84A-04/SO remains a classic choice for developers seeking a proven, well-documented, and easy-to-use 8-bit microcontroller with the invaluable advantage of on-board, reprogrammable non-volatile data memory.
Keywords: PIC16F84A, EEPROM Data Memory, RISC Architecture, In-Circuit Serial Programming (ICSP), 8-bit Timer/Counter.
