Alphanumeric LCD generally HD44780 model is very popular display . This LCD use 8 pins for data display and three pin for control and al together 16 pin . There will be problem on project if we have to connect numbers of components in single microcontroller to make a compact type of device . To reduce number of pin used in this tutorial we are going to make a serial LCD using data shifting technique .
In This project i am going to show you how to convert your parallel LCD display to serial LCD . Serial LCD is a little bit expensive but if we know this technique we can easily make cheap serial LCD by adding a 74HC595 chip .
code for this project is shown below
How this works ?
74hc595 is a kind of shift register . This chip converts serial data to parallel data (in this project we are connecting LCD on 4 bit mode this mode also shift remaining 4 bit data to higher register bit inside the LCD ) , so we are not doing anything new , we are just converting serial data into parallel so that we can reduce number of pin used on microcontroller .The shift register holds what can be thought of as eight memory locations, each of which can be a 1 or a 0.
To set each of these values on or off, we feed in the data using the ‘Data’ and ‘Clock’ pins of the chip. The clock pin needs to receive eight pulses, at the time of each pulse, if the data pin is high, then a 1 gets pushed into the shift register, otherwise a 0. When all eight pulses have been received, then enabling the ‘Latch’ pin copies those eight values to the latch register. This is necessary, otherwise the wrong LEDs would flicker as the data was being loaded into the shift register. You can learn more about this chip on its data seet download here
you can download complete project with code and proteus file , hex file from this link
Please share this project if you think this is useful to you .