Tag Archives: atmega8

Easy 24C I2C Serial EEPROM Interfacing with AVR Microcontrollers

In this turorial we will see how we can easily interface a 24C series serial EEPROM with AVR microcontrollers. What is an EEPROM? An EEPROM is kinds of novalatile memory, that means it is used for storing digital data permanently without any power suply. EEPROM stands for Electrically Erasable Programmable Read Only Memory. The advantage of these kind of ROMs is that they can be erased Electrically to make them ready for storing new data. Compare this with a CD R disks they can be recorded only once. A small amount of EEPROM is also available internally on the AVR chips. So if the volume of data you want to store is small (say few user names and password) then you can use it. The internal eeprom makes design small and simple. But if the amount of data you want to store is large, say in order of few tens of kilobytes then you have to interface a External EEPROM chip with your AVR MCU. You can store pictures, sound and long texts in these eeproms. Their are many kinds of EEPROM chip available from many manufactures. One very common family is 24C series serial EEPROMs. They are available upto 128KB in size. They uses I2C interface with host controller (MCU) which is a very popular serial communication standard. I […]

Using the USART of AVR Microcontrollers : Reading and Writing Data

Till now we have seen the basics of RS232 communication, the function of level converter and the internal USART of AVR micro. After understanding the USART of AVR we have also written a easy to use function to initialize the USART. That was the first step to use RS232. Now we will see how we can actually send/receive data via rs232. As this tutorial is intended for those who are never used USART we will keep the things simple so as to just concentrate on the "USART" part. Of course after you are comfortable with usart you can make it more usable my using interrupt driven mechanism rather than "polling" the usart. So lets get started! In this section we will make two functions :- USARTReadChar() : To read the data (char) from the USART buffer. USARTWriteChar(): To write a given data (char) to the USART. This two functions will demonstrate the use of USART in the most basic and simplest way. After that you can easily write functions that can write strings to USART. Reading From The USART : USARTReadChar() Function. This function will help you read data from the USART. For example if you use your PC to send data to your micro the data is automatically received by the USART of AVR and put in a buffer […]

Interfacing Temperature Sensor – LM35

By interfacing different types of sensors with our MCU we can sense the environment and take decisions, in this way we can create "smart" applications. There are wide variety of sensors available. In this tutorial we will learn about a popular sensor LM35 which is precision centigrade temperature sensor. It can be used to measure temperature with accuracy of 0.5 degree centigrade. We can interface it easily with AVR MCUs and can create thermometers, temperature controller, fire alarms etc. Things Required   S. No. Item Image 1 28 PIN AVR Dev Board Contains the core AVR circuit including 5v regulator, reset, ISP. 2 Seven Segment Display Module Four common anode displays multiplexed with driver transistors and current limiting resistors. 3 Single Pin Female to Female Burg Wires Used to interconnect the two boards. And the sensor.   4 USB AVR Programmer To upload the program to the development board. 5 LM35 Temperature Sensor   LM35 LM35 by National Semiconductor is a popular and low cost temperature sensor. It is also easily available. You can buy one from here online. It has three pins as follows. Fig – LM35 Pin Configuration     The Vcc can be from 4V to 20V as specified by the datasheet. To use the sensor simply connect the Vcc to 5V ,GND to Ground and the […]

Using LCD Module with AVRs

When you start working with LCD modules you will start feeling the real power of MCU and your imaginations will be touching sky you will wonder how many exciting a powerful gadgets you can create and that’s so very easily. LCD Modules can present textual information to user. It’s like a cheap “monitor” that you can hook in all of your gadgets. They come in various types. The most popular one can display 2 lines of 16 characters. These can be easily interfaced to MCU’s, thanks to the API( Functions used to easily access the modules) we provide. LCD interfacing is just fun ! Fig: A 16×2 LCD Module Buy LCD Modules Online In India   PIN Configurations. The lcd modules has 16 PINs for interfacing. The details are given below. LCD Module Pin Configuration 1 VSS (GND Supply) 2 VCC (+5V) 3 VEE (Contrast Adjust) 4 RS 5 R/W 6 E 7 DB0 8 DB1 9 DB2 10 DB3 11 DB4 12 DB5 13 DB6 14 DB7 15 LED + 16 LED –   Connection with ATmega8/ATmega168 etc. The lcd module can be easily connected to the any 28 pin AVR MCU like ATmega8/ATmega168/ATmega328 etc. The diagram below shows the LCD connection with AVR MCUs port pins. Fig: Connection with 28 PIN AVR MCUs Connect the required pins of […]