USB Development Board for PIC18F4550

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This article shows how to make a low cost USB development board for PIC18F4550 similar to Microchip’s PICDEM USB FS board. The Microchip’s USB stack examples can be compiled and loaded directly without altering the code. Access to each of the 40 pins is provided through female headers so that the connections could be extended to a breadboard easily during prototyping. The board has got a LM7805 voltage regulator with a polarity protection. This board will be very helpful in prototyping PIC based USB projects.

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50 MHz range frequency counter using AT90S2313

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A wide range frequency meter is an useful tool for an electronics lab. This projects describes a frequency meter based on AT90S231 microcontroller that can measure input frequencies up to 50 MHz. The measured frequency is displayed on 6 digit multiplexed seven segment displays. It uses two external high-speed 8-bit counters (74HC590) in cascade to count the incoming pulses. Depending upon the input frequency, the counting interval for the external counter circuit is changed by the microcontroller for getting better accuracy. The firmware for AT90S231 is provided in C.

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PIC based shaking LED dice

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Electronics dice projects using push buttons are available all over the internet. This one is a little bit different. It is meant to provide the real feeling of shaking a dice by using a spring with weight and a wire. The two make and break contacts when shaken. The PIC16F688 microcontroller detects the contacts between the spring and the wire, and rolls the dice. After the spring motion stopped completely, the dice output number is displayed with glowing LEDs.

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Easy Data Logger with Virtual USB

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“V-USB is a software-only implementation of a low-speed USB device for Atmel’s AVR® microcontrollers, making it possible to build USB hardware with almost any AVR® microcontroller, not requiring any additional chip.” For further details on V-USB and licensing, visit http://www.obdev.at/products/vusb/index.html This is a data logger project that reads an analog signal, converts into digital number, and sends it to a host computer using Virtual USB. This is a good example application of V-USB. An 8-pin ATtiny45 microcontroller without an external crystal oscillator is used for this demonstration. The beauty of this project is the ATtiny45 presents itself as a USB

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External Interrupts in Atmega AVR

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An interrupt is a process of forcing a microcontroller to temporarily suspend the current job and perform a higher priority task. Once the new request is served, the micrcontroller resumes the original task. Interrupts are powerful tools in embedded system design, and special cares must be taken while implementing them. This tutorial teaches how to use an external and pin change interrupts on an AVR microcontroller. Read

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