Wednesday, August 31, 2011

HD44780 16x2 Char LCD Interfacing with microcontroller

    An alphanumeric low cost LCD Display is very essential for may small and big projects to Display various type of information. Hitachi HD44780  Chipset based 16x2 char LCD is Really very cheap and easily available in the local market.

Project Description:-

  In this project we are going to learn various things about this chip set and displaying text on this LCD. The HD44780 16x2 char LCD screen Use 8bit and 4 bit parallel interface with backlight.

This Primary Objective in this project are:-

1.  Displaying  "Hello Word!! LCD " message on the scree.
2.   Interfacing The LCD to the Microcontroller Using 8bit  Mode and 4 Bit Mode.
3.  Generating and Displaying Custom Char on the LCD Screen. clik here for custom char

Nokia 3315 / 3310 LCD interfacing with Microcontroller

    Displaying content on a normal alphanumeric display is very limited ,we have to be limited with the font size and we can't draw any graphics also. but convention Graphics lcd are really very expensive so here is the solution, you can use Nokia 3315 / 3310 monochrome  LCD to display your large font text and graphics . the reason behind using this LCD is ,it is really very cheap and can be powered with 3 volts supply. so it is really good for battery powered application.

Project Description 

       however you can use almost any microcontroller (with capability to work on 3v ) do display content on this LCD, may be that micro controller is PIC , AVR or MSP 430 , but in this demonstration we will be using Microchip PIC 18F458 Microcontroller.

    The software program for this project will be written in C with MPLAB IDE , This LCD has a resolution of 84x48 pixel.

Circuit Description

Circuit Diagram of  Nokia 3315/3310 interface with micro controller

Accurate LC inductance /Capacitance Meter

About The Project 

This is accurate home made LC inductance/capacitance meter built with very common components which are very easy to find all around . The range of this LC Meter is extremely good at measuring very low value of capacitance and inductance.

LC Meter's Inductance Measurement Ranges:
- 10nH - 1000nH
- 1uH - 1000uH
- 1mH - 100mH

LC Meter's Capacitance Measurement Ranges:
- 0.1pF - 1000pF
- 1nF - 900nF

it auto calibrate when power up , so there is no chances of human error in calibration. we can also re calibrate at any instance of time by pressing the reset button.this meter is completely auto range.


  • No particularly accurate components are required, except for one (or more) accurately known "external" capacitors used to calibrate the meter.
  • The two 1000pF capacitors should be fairly good quality. Polystyrene are preferred. MKT are fine. Greencaps tend to drift in value too much. Avoid ceramic capacitors. Some of these can have high losses (and it is hard to tell).
  • The two 10uF capacitors in the oscillator should be tantalum (for low series resistance/inductance).
  • The 4MHz crystal should be a genuine 4.000MHz one, not something approximate to 4MHz. Every 1% error in crystal frequency adds 2% error to the indicated inductance value.
  • The relay should be a low current one. The PIC can only provide about 30mA of drive current.
  • Don't forget the "catch" diode across the relay coil!

Microchip SPI Basics Tutorial For PIC18

             The Serial Peripheral Interface (SPI) is one of the popular embedded serial communications widely supported by many of today’s chip manufacture and it considered as one of the fastest serial data transfer interface for the embedded system. Because of its special in/out register configuration, the SPI master device could transfer its data and at the same time it receive a data from the SPI slave device with the clock speed as high as 10 MHz. Beside its superior data transfer speed; SPI also use a very simple data transfer protocol compared to the other serial data transfer methods. When the SPI master device want to send the data to the SPI slave device then the SPI master will just simply shifting its own data through a special 8-bits register and at the same time the SPI master will receive the data from the SPI slave into the same register as shown on this following picture.

           With this circular shift register connection between the SPI master and the SPI slave devices, the complete data transfer from both devices will be accomplished in just 8 clock cycles. This means the SPI devices only need about 0.8 us to complete transfer the 8-bit data if we use 10 MHz clock. One of the drawbacks using the SPI especially when we use multiple SPI slave device is the SPI slave could not initiate sending its own data to the SPI master device, all the data transfer initiation is always come from the SPI master. The SPI master device has to poll each of the SPI slave devices to know whether the SPI slave device has a data to be sent to the SPI master device or not.

           Polling the entire SPI slave devices will eventually consumed the SPI master resources when the SPI slave devices to be polled increase, therefore some of the SPI slave device is equipped with the interrupt pin to notify the SPI master device that it has a data to be read.