Frecuency meter

World Academy of Science, Engineering and Technology 42 2008

Implementation of PIC based Digital Frequency Counter
Wai Phyo Aung

Abstract—The main process of this research is to display the
frequency ranges of input frequency. Any desired input frequency from 10Hz to 30 MHz can be counted and displayed using Peripheral Interfacing Controller (PIC) 16f84A and seven digits of Seven SegmentLight emitting diodes (LED) display. The input frequency is counted by PIC16F84A and the output from this PIC pins are decoded by analog multiplexer, 4051 Integrated Circuit (IC). Seven digits are displayed by passing seven NPN Bipolar Junction transistors (BJT), BC547.The main desired output is the high resolution display in MHz range of frequency. Studying the PIC Microcontroller, seven segmentsLED display and the decoders are included in this research. PIC Assembler Software Techniques are also implemented with this research. In this research, the complete design of the advanced frequency Counter is provided. By the help of components, such as, transistors, diodes, the hardware and software technology are combined and developed in this project.

Keywords—Input frequency, PeripheralInterfacing Controller (PIC), Seven Segment Light emitting diodes (LED), 4051 Integrated Circuit (IC), BC547 BJT, Assembler Software Techniques, hardware and software technology. I. INTRODUCTION N several occasions counting is required, but manual counting becomes time-consuming and inaccurate when objects to be connected are very large in number or they pass through in quick succession. In suchsituations, counter using electronic circuits are more reliable then manual counting. A counter with suitable connectivity can work as a stopwatch, or as frequency counter. Various types of frequency counter may have analogue or digital forms. Some of the instruments commonly used for measuring various frequency ranges are, Oscilloscopes, Wein Bridge Frequency Meters, Zero-beat Frequency Meters,Direct reading Frequency Meters, Binary Frequency Counters, Digital Frequency Counters and University time-counters. The oscilloscope can measure a wide range of frequencies. However, the accuracy of oscilloscope is somewhat limited. The Wein Bridge Frequency Meter is a device designed only to produce accurately known audio-frequency signals. Zerobeat Frequency Meter is used to measure theradio-frequency range. The University time-counter can be used to measure both frequency and time intervals. But it can be only used to
Manuscript received August 15, 2008. This work was supported in part by the Ministry of Science and Technology, Union of Myanmar. Wai Phyo Aung is with the Mandalay Technological University, Mandalay, Myanmar (phone: 095-2-88704(Electronic Engineering Department), fax:095-2-88702 (Office,MTU), e-mail: aungwp@gmail.com).

accurately measure low frequencies instead of frequency counters. Digital frequency counters are the most accurate and flexible instruments available for measuring unknown frequencies. Frequencies from dc to the giga-hertz range can be measured with digital frequency counters. In this thesis, the author used the most advanced microcontroller tobuild the digital frequency counter. Most modern microcontrollers have the following built-in features: 1. Built-in monitors /debugger program 2. Built-in program memory program-ming from a direct host connection 3. Interrupt capability (from a variety of sources) 4. Analog input and output 5. Serial input and output 6. Bus / external memory interfaces (for RAM and ROM) PIC microcontroller hasbecome a real powerhouse with regards to available support. In many ways, the PIC microcontroller has more support available than other electronics device. In this research, the PIC 16F84A is used to construct a high resolution frequency counters which can measure up to 30 MHz. II. HARDWARE DESIGN OF PIC BASED FREQUENCY COUNTER The frequency counter to be designed in this research is the PIC 16F84A...