Objective

If you have done with simple 16x2 LCD and still want to do more with display, its time to have fun with Graphics LCD.

We all really enjoy animations kind of things and this is the stuff what we can do with GLCD.

GLCD is very similar to simple 16x2 LCD with additional features. To explore these features and functionality you would like to see our tutorial Graphics LCD Basics : KS0108 based JHD12864E

Schematic

Schematic

Port Connection

This section shows how to configure the GPIO for interfacing the GLCD.
The below configuration is as per the above schematic. You can connect the GLCD to any of the PORT pins available on your boards and update this section accordingly

GLCD Operation

In this section we are going to see how to send the data/cmd to the GLCD along with the timing diagrams. First lets see the timing diagram for sending the data and the command signals(RS,RW,EN), accordingly we write the algorithm and finally the code.

Timing Diagram

The below image shows the timing diagram for sending the data to the GLCD.
As shown in the timing diagram the data is written after sending the RS and RW signals. It is still ok to send the data before these signals.
The only important thing is the data should be available on the databus before generating the High-to-Low pulse on EN pin.

figure: command write



Steps for Sending Command:

  • step1: Send the I/P command to GLCD.
  • step2: Select the Control Register by making RS low.
  • step3: Select Write operation making RW low.
  • step4: Send a High-to-Low pulse on Enable PIN with some delay_us.

Steps for Sending Data:

  • step1: Send the character to GLCD.
  • step2: Select the Data Register by making RS high.
  • step3: Select Write operation making RW low.
  • step4: Send a High-to-Low pulse on Enable PIN with some delay_us.

The timings are similar as above only change is that RS is made high for selecting Data register.

Code Example

Example 1

Let's start with displaying some text.

Using Explore Embedded Libraries

In the above example we just discussed how to interface Graphics Lcd.
Once you know the working of GLCD, you can directly use the ExploreEmbedded libraries to play around with your GLCD.
For that you need to include the glcd.c/glcd.h and the associated files(delay/stdutils).
The below sample code shows how to use the already available GLCD functions.

Refer this link for more info on GLCD libraries.

Explore Embedded Graphics Library

GLCD_SetDot ()
{{#Widget:LibTable}}
Defination void GLCD_SetDot ( uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_color_u8 )
Input Arguments
  • var_x_u8 : x coordinate of left side end point of line ( 0 to 127 )
  • var_y_u8 : y coordinate of left side end point of line ( 0 to 63 )
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw a dot
Usage
Output Glcd set dot.png
GLCD_DrawHoriLine()
{{#Widget:LibTable}}
Defination void GLCD_DrawHoriLine(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_length_u8,uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of left side end point of line ( 0 to 127 )
  • var_y_u8 : y coordinate of left side end point of line ( 0 to 63 )
  • var_length_u8: length of line
  • var_color_u8  : color of pixels ( 0 or 1)
Return Value none
Description This function is used to draw horizontial line.
Usage

Output Glcd horizontial line.png
GLCD_DrawVertLine()
{{#Widget:LibTable}}
Defination void GLCD_DrawVertLine(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_length_u8,uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of left side end point of line ( 0 to 127 )
  • var_y_u8 : y coordinate of left side end point of line ( 0 to 63 )
  • var_length_u8: length of line
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw vertical line.
Usage

Output Glcd verticl line.png
GLCD_DrawLine()
{{#Widget:LibTable}}
Defination void GLCD_DrawLine ( uint8_t var_x1_u8, uint8_t var_y1_u8, uint8_t var_x2_u8, uint8_t var_y2_u8, uint8_t var_color_u8)
Input Arguments
  • var_x1_u8 : x coordinate of end point of line (0 to 127)
  • var_y1_u8 : y coordinate of end point of line (0 to 63)
  • var_x2_u8: x coordinate of other end point of line
  • var_y2_u8: y coordinate of other end point of line
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw line.
Usage
Output Glcd line.png
GLCD_DrawRect()
{{#Widget:LibTable}}
Defination void GLCD_DrawRect(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_width_u8, uint8_t var_height_u8, uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of top left side vertex of rectangle (0 to 127)
  • var_y_u8 : y coordinate of top left side vertex of rectangle (0 to 63)
  • var_width_u8 : width of rectangle
  • var_height_u8 : height of rectangle
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw rectangle.
Usage
Output Glcd rectangle.png
GLCD_DrawRoundRect()
{{#Widget:LibTable}}
Defination void GLCD_DrawRoundRect(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_width_u8, uint8_t var_height_u8, var_radius_u8, uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of top left side vertex of rectangle ( 0 to 127 )
  • var_y_u8 : y coordinate of top left side vertex of rectangle ( 0 to 63 )
  • var_width_u8 : width of rectangle
  • var_height_u8 : height of rectangle
  • var_radius_u8 : radius of circular part at corner
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw round rectangle.
Usage
Output Glcd ound rectangle.png
GLCD_DrawFillRect()
{{#Widget:LibTable}}
Defination void GLCD_DrawFillRect(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_width_u8, uint8_t var_height_u8, uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of top left side vertex of rectangle (0 to 127)
  • var_y_u8 : y coordinate of top left side vertex of rectangle (0 to 63)
  • var_width_u8 : width of rectangle
  • var_height_u8 : height of rectangle
  • var_color_u8  : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw filled rectangle.
Usage GLCD_DrawFillRect(23,13,80,40,1);
Output Glcd fill rectangle.png
GLCD_InvertRect()
{{#Widget:LibTable}}
Defination void GLCD_InvertRect(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_width_u8, uint8_t var_height_u8)
Input Arguments
  • var_x_u8 : x coordinate of top left side vertex of rectangle (0 to 127)
  • var_y_u8 : y coordinate of top left side vertex of rectangle (0 to 63)
  • var_width_u8 : width of rectangle
  • var_height_u8 : height of rectangle
Return Value none
Description This function is used to invert the selected rectangular area
Usage GLCD_InvertRect(18,8,80,50);
GLCD_InvertRect(28,18,60,30);
GLCD_InvertRect(38,28,40,10);
Output Glcd invert rectangle.png
GLCD_DrawCircle()
{{#Widget:LibTable}}
Defination void GLCD_DrawCircle(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_radius_u8, uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of center of circle (0 to 127)
  • var_y_u8 : y coordinate of center of circle (0 to 63)
  • var_radius_u8 : radius of circle
  • var_color_u8 : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw circle.
Usage GLCD_DrawCircle(60,30,30,1);
GLCD_DrawCircle(60,30,20,1);

GLCD_DrawCircle(60,30,10,1);

Output Glcd cirlce.png
GLCD_DrawFillCircle()
{{#Widget:LibTable}}
Defination void GLCD_DrawFillCircle(uint8_t var_x_u8, uint8_t var_y_u8, uint8_t var_radius_u8, uint8_t var_color_u8)
Input Arguments
  • var_x_u8 : x coordinate of center of circle (0 to 127)
  • var_y_u8 : y coordinate of center of circle (0 to 63)
  • var_radius_u8 : radius of circle
  • var_color_u8 : color of pixels ( 0 or 1 )
Return Value none
Description This function is used to draw filled circle.
Usage GLCD_DrawFillCircle(60,30,30,1);
Output Glcd fill circle.png
GLCD_DisplayVerticalGraph()
{{#Widget:LibTable}}
Defination void GLCD_DisplayVerticalGraph(uint8_t var_barGraphNumber_u8, uint8_t var_percentageValue_u8)
Input Arguments
  • var_barGraphNumber_u8 : position of bar ( 0 to 3 )
  • var_percentageValue_u8 : value of the bar in percentage
Return Value This function displays bar graph in vertical direction
Description This function is used to draw filled circle.
Usage GLCD_DisplayVerticalGraph(0,45);
GLCD_DisplayVerticalGraph(1,50);
GLCD_DisplayVerticalGraph(2,82);
GLCD_DisplayVerticalGraph(3,74);
Output Glcd vertical graph.png
GLCD_DisplayHorizontalGraph()
{{#Widget:LibTable}}
Defination void GLCD_DisplayHorizontalGraph(uint8_t var_barGraphNumber_u8, uint8_t var_percentageValue_u8)
Input Arguments
  • var_barGraphNumber_u8 : position of bar ( 0 to 3 )
  • var_percentageValue_u8 : value of the bar in percentage
Return Value This function displays bar graph in horizontial direction
Description This function is used to draw filled circle.
Usage GLCD_DisplayHorizontalGraph(0,45);
GLCD_DisplayHorizontalGraph(1,50);
GLCD_DisplayHorizontalGraph(2,82);
GLCD_DisplayHorizontalGraph(3,74);
Output Glcd horizontial graph.png


Lots of things are there which you would like to do with GLCD and we will cover it in the future tutorials. For now, you don't forget to comment.