August | 2011 | Embedded Lab

Monthly Archives: August 2011

Lab 18: Matrix keypad interfacing

Posted on August 25, 2011 by R-B 9 comments

Matrix keypads are very common input devices in embedded systems. They have simple architecture and are easy to interface. One good thing about them is that they allow you to interface a large number of input keys to a microcontroller with minimum usage of I/O resources. This tutorial describes two different approaches of reading input data from a 4×4 (16 keys) matrix keypad interfaced to a PIC microcontroller. The pressed key information is displayed on a character LCD. The microcontroller used in this experiment is PIC16F1827.

Stereo audio amplifier using TEA2025 chip

Posted on August 14, 2011 by R-B 33 comments

While LM386 is the most popular audio amplifier IC among hobbyists, it provides the limited output power of only 1 Watt, and for stereo application, two LM386 ICs are required. This project is about making a 5 Watt stereo audio amplifier using the UTC TEA2025 IC chip.

Lab 17: Sleep and Wake PIC microcontrollers

Posted on August 6, 2011 by R-B 32 comments

PIC microcontrollers’ Sleep feature is an extremely useful mechanism to minimize power consumption in battery-powered applications. In Sleep mode, the normal operation of a PIC microcontroller is suspended and the clock oscillator is switched off. The power consumption is lowest in this state. The device can be woken up by an external reset, a watch-dog timer reset, an interrupt on INT0 pin, or port-on-change interrupt. In this experiment, we will discuss how to put a PIC microcontroller into Sleep mode and compare the current consumption during Sleep mode and the normal operation mode.