 Hello, Myself Ravindra Chauhan, Assistant Professor, Department of Electronics Engineering, Vulturend instead of Technology, SolarPort. Today in this session, we will discuss how to interface the graphical LCD with the microcontroller 8051. The outcome of this particular session, at the end of the session student will be able to develop the controller based system with the graphical LCD. Outline of the session is like this, so the internals and pinout of the graphical LCD, page line and cursor selection of the graphical LCD, the commands for the graphical LCD, steps for sending the commands and data to the LCD, and then how to interface the LCD with the 8051. So overview of graphical LCD, the LCD stands for liquid crystal display, and graphical LCD is used to display anything. The LCDs are classified in mainly the two types, the character LCD and the graphical LCD. The character LCD are displayed certain characters, for example 16 by 2 LCD, so we can display the total 32 characters and 16 characters on each line. So the 16 by 2 LCD consists of two lines and 16 columns. Graphical LCD are used to display the customized characters and images, and mainly it is used in the video games, mobile phones, lifts etc. as a display unit. This is the internal of the graphical LCD. The example shown is for 128 by 64 graphical LCD, so 128 columns and the 64 rows are there. Again these 128 columns are divided in two pages, page 0 and page 1 with 64 columns on each page. So lower 64 that is 0 to 63 pixels are controlled by the control driver circuit IC1 and IC2 which will drive the upper 64 to 127 pixels. So the 128 pixels on x axis and 64 pixels on y axis. Further the x axis is divided into two parts of 64 pixels, so lower 64 pixels with 0 to 63 and higher 64 pixels from 64 to 127. And each part is controlled by the unique controller slash driver IC. In the previous slide we have shown the two driver circuits that is the IC1 and IC2 which will control the lower 64 pixels and the higher 64 pixels by IC2. Now coming to the pinout of the graphical LCD, the normally pin number one is VSS that is the ground, pin number two is the VCC which is need to be connected to the plus five hold. Then pin number three is the V0 which is to be used to adjust the contrast of the display. Then the pin number four is called register select that is RS slash data instruction. Now this RS is to be kept at low when we are sending the command or instruction to the LCD and when we are sending the actual character to be displayed at that time this RS should be kept at logic high. So to decide the read write operation the pin number five is to be used that is called the read write. For write operation it should be low and for read operation it should be high. Now as far as the LCD is concerned mainly it is used to display the characters. So most of the times it is required to perform the write operation. So for what purpose this read operation is provided? So what we can read from the LCD? So only one read operation is possible. By doing this by reading the LCD we can check out whether the LCD is busy or not. So we can only read the status of the graphical LCD. So the pin number six is called the enable pin and it is required to apply the negative pulse on the enable pin so that whatever the data available on the data pins that will be gets latched into the LCD. Then pin number seven to thirteen that is D zero to D six the lower seven data bits and higher eight bit that is the bit D seven is defined on pin number fourteen and it is also called the busy flag means we can check whether the LCD is busy or not by monitoring the status of D seven bit. Then the two chip select bits are provided CS1 and CS2 for selecting the two pages of the LCD RST will reset the LCD module and the VEE which is pin number eighteen it is to be used to adjust the brightness of the display. Then this is the look of the graphical LCD page and line. So here you will see the lower sixty three bits and lower sixty four bits and higher sixty four bits are divided in two parts and then it is required to select the either left or right part of the particular page and each page is consists of the eight lines. So to display the any character it is required to select the particular page and particular line and then we can decide the cursor position. Now you just see the previous slide and consider this LCD as a open book with two pages consisting of eight lines on each page. So each line has sixty four cursor positions to display the data slash images. So the required page can be selected page means the lower sixty four pixel or higher sixty four pixel. So that is called the page and this can be selected by using the two chip select bits CS1 and CS2. So when CS1 and CS2 both are zero no page will be selected. Then to select the lower sixty four pixels which we can say as a page zero make CS1 one and kept CS2 at logic zero to select the higher sixty four pixels that is the sixty four to one hundred and twenty seven connect CS2 at logic high and kept CS1 at logic zero and when both are one then both the pages will be get selected. So for the line selection to select the line it is required to send the respective command or the line address to the graphical LCD. Then the line addresses starts from the B8 and goes till BF. Eight lines are there so their address starts from B8. The next line address will be B9 then the BA, BC up to BF which is the address of line number seven. Then to decide the cursor positions okay so to set the cursor positions zero to sixty three we need to send its address to the graphical LCD and the cursor position address starts from forty that is the cursor position zero and goes till seven F. Now this is the interfacing of the graphical LCD with the 8051. So port one is used for data P2.0, P2.2 and 2.1 are used for the three control signals and P2.3 and P2.4 is for the page selection. Now steps for sending the command so you just pause the video and recall the steps to send the command to LCD. So steps for sending the command first send the required command to LCD then select the control register by making RS low then select the write operation by making read write low then send high to low pulse on enable pin with some delay which is in microsecond. Similarly steps for sending the data send the data to LCD select the control register by making RS high then select write operation making read write low and send high to low pulse on enable pin. So steps used for this presentation is mainly the literature from Punit Verma and the book by Majidi and Majidi. Thank you.