Description: Matrix keypads are well known for their simple architecture and ease of interfacing with any microcontroller. In order to detect which key is pressed from the matrix, we make row lines low one by one and read the columns. To scan the keypad completely, we need to make rows low one by one and read the columns. If any of the buttons is pressed in a row, it will take the corresponding column to a low state which tells us that a key is pressed in that row. If button 1 of a row is pressed then Column 1 will become low, if button 2 then column2 and so on...

Lab 3: Interfacing RTC DS1307 with Microcontroller

Description: DS1307 is one device that used widely in microcontroller applications. It provides Serial Real Time Clock is a low–power, full BCD clock/calendar plus 56 bytes of nonvolatile SRAM. Address and data are transferred serially via the 2–wire bi–directional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The software will read all data from RTC then send to PC via RS232 interface with baud rate 9600,8,N,1. In main loop just read and send data every 500 ms to refresh Hyper terminal program.

Lab 4: 16x2 LCD interfacing with Microcontroller

Description: One of the most common devices attached to an 8051 is an LCD display. The most common LCD connected to the 8051 is 16x2 display. This means 16 characters per line by 2 lines. LCD modules have 8-bit data interface and control pins. One can send data as 8-bit. To display any character on LCD micro controller has to send its ASCII value to the data bus of LCD.

Description: The Light Emitting Diode (LED) finds its place in many applications in this modern electronic field. One of them is the Seven Segment Display. Seven-segment displays contains the arrangement of the LED’s in “Eight” (8) passion, and a Dot (.) with a common electrode, lead (Anode or Cathode). The purpose of arranging it in that passion is that we can make any number out of that by switching ON and OFF the particular LED's. The common cathode pin is connected to GND by external wire, if it is the CC LED and in the case of the common Anode LED, the Anode pin is connected to +Vcc. Here, other pins of the LED are connected to Port (0, 1, 2 or 3) of microcontroller.

Description: UART (Universal Asynchronous Receiver Transmitter) or USART (Universal Synchronous Asynchronous Receiver Transmitter) are one of the basic interfaces which you will find in almost all the controllers available in the market till date. This interface provides a cost effective simple and reliable communication between one controller to another controller or between a controller and PC.

Description: In lot of embedded systems micro controllers needs to take analog input. Most of the sensors and transducers such as temperature, humidity, pressure, are analog. For interfacing these sensors with micro controllers we require to convert the analog output of these sensors to digital, so that the controller can read it. One of the most commonly used ADC is ADC0804. ADC 0804 is a Successive approximation type with 8 channels i.e. it can directly access 8 single ended analog signals.

Description: In this project a D.C. motor is interfaced to AT89C51 where the operation of the motor is controlled. The operation is to turn the motor on and turn the motor off. D.C. motor operates at 6v it is connected to one of the GPIO pins of the microcontroller. When the pin is set high motor turns on and when the pin goes low motor turns off.