pin assignment for tft lcd and arduino brands
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In this article, you will learn how to use TFT LCDs by Arduino boards. From basic commands to professional designs and technics are all explained here.
In electronic’s projects, creating an interface between user and system is very important. This interface could be created by displaying useful data, a menu, and ease of access. A beautiful design is also very important.
There are several components to achieve this. LEDs, 7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.
TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.
In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.
In this article, we have used libraries and advanced technics to display data, charts, menu, etc. with a professional design. This can move your project presentation to a higher level.
In electronic’s projects, creating an interface between user and system is very important. This interface could be created by displaying useful data, a menu, and ease of access. A beautiful design is also very important.
There are several components to achieve this. LEDs, 7-segments, Character and Graphic displays, and full-color TFT LCDs. The right component for your projects depends on the amount of data to be displayed, type of user interaction, and processor capacity.
TFT LCD is a variant of a liquid-crystal display (LCD) that uses thin-film-transistor (TFT) technology to improve image qualities such as addressability and contrast. A TFT LCD is an active matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven LCDs with a few segments.
In Arduino-based projects, the processor frequency is low. So it is not possible to display complex, high definition images and high-speed motions. Therefore, full-color TFT LCDs can only be used to display simple data and commands.
In this article, we have used libraries and advanced technics to display data, charts, menu, etc. with a professional design. This can move your project presentation to a higher level.
Size of displays affects your project parameters. Bigger Display is not always better. if you want to display high-resolution images and signs, you should choose a big size display with higher resolution. But it decreases the speed of your processing, needs more space and also needs more current to run.
After choosing the right display, It’s time to choose the right controller. If you want to display characters, tests, numbers and static images and the speed of display is not important, the Atmega328 Arduino boards (such as Arduino UNO) are a proper choice. If the size of your code is big, The UNO board may not be enough. You can use Arduino Mega2560 instead. And if you want to show high resolution images and motions with high speed, you should use the ARM core Arduino boards such as Arduino DUE.
In electronics/computer hardware a display driver is usually a semiconductor integrated circuit (but may alternatively comprise a state machine made of discrete logic and other components) which provides an interface function between a microprocessor, microcontroller, ASIC or general-purpose peripheral interface and a particular type of display device, e.g. LCD, LED, OLED, ePaper, CRT, Vacuum fluorescent or Nixie.
The display driver will typically accept commands and data using an industry-standard general-purpose serial or parallel interface, such as TTL, CMOS, RS232, SPI, I2C, etc. and generate signals with suitable voltage, current, timing and demultiplexing to make the display show the desired text or image.
The LCDs manufacturers use different drivers in their products. Some of them are more popular and some of them are very unknown. To run your display easily, you should use Arduino LCDs libraries and add them to your code. Otherwise running the display may be very difficult. There are many free libraries you can find on the internet but the important point about the libraries is their compatibility with the LCD’s driver. The driver of your LCD must be known by your library. In this article, we use the Adafruit GFX library and MCUFRIEND KBV library and example codes. You can download them from the following links.
You must add the library and then upload the code. If it is the first time you run an Arduino board, don’t worry. Just follow these steps:Go to www.arduino.cc/en/Main/Software and download the software of your OS. Install the IDE software as instructed.
By these two functions, You can find out the resolution of the display. Just add them to the code and put the outputs in a uint16_t variable. Then read it from the Serial port by Serial.println(); . First add Serial.begin(9600); in setup().
First you should convert your image to hex code. Download the software from the following link. if you don’t want to change the settings of the software, you must invert the color of the image and make the image horizontally mirrored and rotate it 90 degrees counterclockwise. Now add it to the software and convert it. Open the exported file and copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are sizes of image. you can change the color of the image in the last input.
Upload your image and download the converted file that the UTFT libraries can process. Now copy the hex code to Arduino IDE. x and y are locations of the image. sx and sy are size of the image.
In this template, We just used a string and 8 filled circles that change their colors in order. To draw circles around a static point ,You can use sin(); and cos(); functions. you should define the PI number . To change colors, you can use color565(); function and replace your RGB code.
In this template, We converted a .jpg image to .c file and added to the code, wrote a string and used the fade code to display. Then we used scroll code to move the screen left. Download the .h file and add it to the folder of the Arduino sketch.
In this template, We used sin(); and cos(); functions to draw Arcs with our desired thickness and displayed number by text printing function. Then we converted an image to hex code and added them to the code and displayed the image by bitmap function. Then we used draw lines function to change the style of the image. Download the .h file and add it to the folder of the Arduino sketch.
In this template, We created a function which accepts numbers as input and displays them as a pie chart. We just use draw arc and filled circle functions.
In this template, We added a converted image to code and then used two black and white arcs to create the pointer of volumes. Download the .h file and add it to the folder of the Arduino sketch.
In this template, We added a converted image and use the arc and print function to create this gauge. Download the .h file and add it to folder of the Arduino sketch.
while (a < b) { Serial.println(a); j = 80 * (sin(PI * a / 2000)); i = 80 * (cos(PI * a / 2000)); j2 = 50 * (sin(PI * a / 2000)); i2 = 50 * (cos(PI * a / 2000)); tft.drawLine(i2 + 235, j2 + 169, i + 235, j + 169, tft.color565(0, 255, 255)); tft.fillRect(200, 153, 75, 33, 0x0000); tft.setTextSize(3); tft.setTextColor(0xffff); if ((a/20)>99)
while (b < a) { j = 80 * (sin(PI * a / 2000)); i = 80 * (cos(PI * a / 2000)); j2 = 50 * (sin(PI * a / 2000)); i2 = 50 * (cos(PI * a / 2000)); tft.drawLine(i2 + 235, j2 + 169, i + 235, j + 169, tft.color565(0, 0, 0)); tft.fillRect(200, 153, 75, 33, 0x0000); tft.setTextSize(3); tft.setTextColor(0xffff); if ((a/20)>99)
In this template, We display simple images one after each other very fast by bitmap function. So you can make your animation by this trick. Download the .h file and add it to folder of the Arduino sketch.
In this template, We just display some images by RGBbitmap and bitmap functions. Just make a code for touchscreen and use this template. Download the .h file and add it to folder of the Arduino sketch.
The speed of playing all the GIF files are edited and we made them faster or slower for better understanding. The speed of motions depends on the speed of your processor or type of code or size and thickness of elements in the code.
The purpose of this application note is to review the RGB interface and discuss any requirements necessary for communicating with the microcontroller through this interface. The display communicates with the microcontroller over 45 pins through an RGB interface. An additional graphics controller is required to use this interface. The graphics controller chosen for this application is the SSD1963 LCD Controller Graphics card.
The display featured in this application note is a transmissive, 5.0” (67.56mmx122.35mm), portrait mode TFT display. The part number for this display is E50RG84885LWAM520-CA. This display has a built in controller IC ILI9806E. This display also has a capacitive touch feature. Features of this display are listed below.
The display used in this application has an internal built-in display controller IC ILI9806E. This controller IC does not contain internal RAM and therefore an additional graphics controller SSD1963 is required to provide the RAM that supports the RGB interface. The ILI9806E controller IC that is built into the display provides the 3-wire serial interface to input the initialization commands for the RGB interface.
Once the initialization commands are sent via the 3-wire serial interface, the graphic controller will be used to send the RGB commands to the display. The SSD1963 graphics controller chip is used to communicate to the RGB interface on the display. The graphics controller provides the SRAM required to drive the display. This controller provides a 1215kB frame buffer to support the 24-bit graphics data to the display.
The graphics controller would not be required if the internal IC embedded in the display contains internal RAM. The specification sheet for the embedded display controller IC should be used to verify this information. The graphics controller chip is accessed after the SPI initialization of the display. The graphics controller chip communicates with the microcontroller through a 16-bit parallel 8080 MCU interface.
The microcontroller in this application is a 32-bit ARM core processor. This device communicates with the display over the serial interface to send the SPI initialization commands. Once completed, the microcontroller will then communicate to the graphics controller through an 8-bit parallel initialization command and then 16-bit graphical data commands and functions.
A review of the connection ports and pins between each device will be specified in this section. Starting with the display and the connections with the graphics controller as well as the microcontroller. The display’s 3 wire serial pins can be directly connected to the microcontroller. The RGB interface pins will be connected to the graphics controller. Below is a description of the pin connections on the display.
The next hardware connection that will be reviewed is between the graphics controller chip and the microcontroller. The two devices are connected through a 16-bit 8080 parallel interface. The graphics controller will receive initialization commands from the microcontroller specifying its own requirements as well as commands that will be sent to the display over the RGB interface. The parallel connection between the microcontroller and the graphics controller are as follows.
The microcontroller provides the logic voltage and logic ground for both the display and the graphics controller. There are two reset pins total, one connected to the display and one for the graphics controller. It is important to only use the reset pin for the SPI initialization and set the graphics controller reset to 3.3V. If the graphics controller reset pin is toggled, the SPI initialization commands stored on the display will be reset as well.
The Arduino Due is connected to both the display and the graphics controller. First the microcontroller sends the SPI initialization commands to the display’s embedded controller IC. Next it will communicate with the graphics controller over an 8-bit 8080 parallel interface to initialize the 16-bit parallel interface parameters. Once both devices are initialized, further commands can be sent through the graphics controller to the display to create an image.
The initialization commands required for the display and graphics controller to start will be reviewed in this section. The microcontroller will need to send two sets of initialization code over each interface. The pins will need to be calibrated to each of their specified interfaces, SPI and 8080 Parallel interfaces. The first set of initialization commands are sent to the display’s SPI pins. This code will define the RGB interface parameters required to use this interface.
This code defines the RGB interface timing characteristics, the resolution of the display, the voltage settings and much more. The initialization commands and data specific to the display can be found in the data sheet of the embedded IC controller ILI9806E. Review the specification sheet for this controller for details on the commands and functions of this code.
To send the data and commands over the SPI interface, four peripheral pins will need to be declared depending on the microcontroller used. Once the data pins are setup the SPI interface can send the initialization code in the following sequence. This code is represented in the following timing diagram as a typical 3-wire SPI interface.
The initialization code for the graphics controller is sent over a parallel 8080 interface. The sequence of commands is to first initialize the graphics controller and specify the display parameters, followed by the code that will be sent over the 16 data buses. The initialization commands for the graphics controller SSD1963 are detailed in the controller’s specification sheet. The code used to initialize the graphics controller can be found here.
The initialization code for the graphics controller defines the parameters of the display and the required timing characteristics. The specifications and timing definitions can be found in the spec sheet of the display. The commands that are sent in this section lets the graphics controller know the details specific to the display that we are using in this example. The data is sent over the 8080-parallel interface to the graphics controller. Below is the timing diagram of this parallel interface.
After the initialization commands for both the display and the graphics controller are sent, the display is now ready for communication. The graphical data or images will be sent to the graphics controller’s RAM to be accessed by the display via the RGB interface. Communication to the display is fast and efficient for transmitting images that are to be displayed. For this example, an application was written to display bitmaps on the screen. Below is the output of this example.
Buyers and others who are developing systems that incorporate FocusLCDs products (collectively, “Designers”) understand and agree that Designers remain responsible for using their independent analysis, evaluation and judgment in designing their applications and that Designers have full and exclusive responsibility to assure the safety of Designers" applications and compliance of their applications (and of all FocusLCDs products used in or for Designers’ applications) with all applicable regulations, laws and other applicable requirements.
Designer agrees that prior to using or distributing any applications that include FocusLCDs products, Designer will thoroughly test such applications and the functionality of such FocusLCDs products as used in such applications.
As I can read your link, the shield is using D2-D8 and A0-A3, leaving some pins unused. So some Arduino pins are still free to use, just the shield is in the way to get connected there.
brutally solder some wires to the shield unused pins from front side and use that wires to connect where you want (sensors, breadboard, universal PCB, ...)
create intermediate shield (there are many, which allow you connect to arduinou on bottom and stack antother shield on top, draw your wires from there (and maybe even put some circuities on the middle shield, if you want
(something like this https://www.aliexpress.com/item/UNO-Prototype-DIY-shield-kit-for-Arduino-UNO-Universal-Extend-Board-UM-UNO/32555004112.html or any "arduino universal shield"
use pins D10-D13 as they are connected also to ISP header https://www.arduino.cc/en/Tutorial/ArduinoISP and could be connected from there. As they are part of SPI interface
It is possible to connect more arduinos, there are so much different ways, that it is hard to write here all - choose one, that would suit you best. (anyway you would need some access to some pins anyway )
You can hook up the "Adafruit_ST7735" or from what i later learned after getting my Esplora. Thats when i had my adruino-epiphany. Okay so IF your wondering why im including this super rad Controller shaped arduino, the answer is, its a leonardo. well its just a different flavor of the Atmega32u4 whis is the chip that made ext serial programmers kinda obsolete and makes the uno and megas so unique as well. so with that being said the Esplora has a native language when refering back the tft libraries, but its not too far from a simple (ctrl+F) and replace Esplora references with actual defines and references. and in this case the Leonardo would need to have the icsp header used by the corresponding pins on the display (for this instance of using an SPI connection with the serial display we will not swap the Miso and Mosi like we would a nother instance.just connect miso to miso and mosi to mosi i usually plug up the whole icsp header and then that wwill leave you with the two pins you MUST DEFINE to make it work which would be :
but the point i had to bring up is that i believe the guy before mentioned that it is a muchslower connectionor process than if it were.....were you saying softwareserial was the option then?
because im not an explert or novice or maker by any means. but i have picked up along the lines that hardware serial will always trump software serial compilation any day once you get your head wrapped around the brevity of what ports and pins are actually what are used or have the data displayed on the serial ports. and like software is a necessity im afraid, but its as simple as reasigning pins and when that gets too hard going out and just bbuying a mega, haahah hope i sorta helped. id say go out and snag an esplora whilst their like toing a fire clearance sale on the originallt 50$+ boards. but their reference and prebuilt array of sensors is a bit underwhelming for the newbies in what it alll does, but kinda overwhelmine and difficult to transistion onece having looked at some code as it is, but the language is more forg9ving, but i believe their also officially retiring the leonardo espolora and micro series so good luck this tft display kicks bum man and is the only one that hsnt broke
I have recently bought a 3.5" TFT LCD (from Ebay) for an Arduino UNO, however I find that it uses nearly all the available UNO pins and in particular most of the analogue pins, 4 of which I was hoping to use as analogue inputs. As I have no intention of using the SD card slot, would it be possible to transfer 4 of the LCD control lines to the pins currently used by the SD card connector?
Physically rewiring the pins looks fairly straightforward, and even though I have rewired the RST from A4 to 13, I still can"t use A4 as an anologue input - as it still appears to be assigned to something.
Hi guys, welcome to today’s tutorial. Today, we will look on how to use the 1.8″ ST7735 colored TFT display with Arduino. The past few tutorials have been focused on how to use the Nokia 5110 LCD display extensively but there will be a time when we will need to use a colored display or something bigger with additional features, that’s where the 1.8″ ST7735 TFT display comes in.
The ST7735 TFT display is a 1.8″ display with a resolution of 128×160 pixels and can display a wide range of colors ( full 18-bit color, 262,144 shades!). The display uses the SPI protocol for communication and has its own pixel-addressable frame buffer which means it can be used with all kinds of microcontroller and you only need 4 i/o pins. To complement the display, it also comes with an SD card slot on which colored bitmaps can be loaded and easily displayed on the screen.
The schematics for this project is fairly easy as the only thing we will be connecting to the Arduino is the display. Connect the display to the Arduino as shown in the schematics below.
Due to variation in display pin out from different manufacturers and for clarity, the pin connection between the Arduino and the TFT display is mapped out below:
We will use two libraries from Adafruit to help us easily communicate with the LCD. The libraries include the Adafruit GFX library which can be downloaded here and the Adafruit ST7735 Library which can be downloaded here.
We will use two example sketches to demonstrate the use of the ST7735 TFT display. The first example is the lightweight TFT Display text example sketch from the Adafruit TFT examples. It can be accessed by going to examples -> TFT -> Arduino -> TFTDisplaytext. This example displays the analog value of pin A0 on the display. It is one of the easiest examples that can be used to demonstrate the ability of this display.
The second example is the graphics test example from the more capable and heavier Adafruit ST7735 Arduino library. I will explain this particular example as it features the use of the display for diverse purposes including the display of text and “animated” graphics. With the Adafruit ST7735 library installed, this example can be accessed by going to examples -> Adafruit ST7735 library -> graphics test.
The first thing, as usual, is to include the libraries to be used after which we declare the pins on the Arduino to which our LCD pins are connected to. We also make a slight change to the code setting reset pin as pin 8 and DC pin as pin 9 to match our schematics.
Next, we create an object of the library with the pins to which the LCD is connected on the Arduino as parameters. There are two options for this, feel free to choose the most preferred.
Next, we move to the void setup function where we initialize the screen and call different test functions to display certain texts or images. These functions can be edited to display what you want based on your project needs.
All the functions called under the void setup function, perform different functions, some draw lines, some, boxes and text with different font, color and size and they can all be edited to do what your project needs.
The complete code for this is available under the libraries example on the Arduino IDE. Don’t forget to change the DC and the RESET pin configuration in the code to match the schematics.
Uploading the code to the Arduino board brings a flash of different shapes and text with different colors on the display. I captured one and its shown in the image below.
That’s it for this tutorial guys, what interesting thing are you going to build with this display? Let’s get the conversation started. Feel free to reach me via the comment section if you have any questions as regards this project.
The 1.8inch LCD uses the PH2.0 8PIN interface, which can be connected to the Raspberry Pi according to the above table: (Please connect according to the pin definition table. The color of the wiring in the picture is for reference only, and the actual color shall prevail.)
The example we provide is based on STM32F103RBT6, and the connection method provided is also the corresponding pin of STM32F103RBT6. If you need to transplant the program, please connect according to the actual pin.
ST7735S is a 132*162 pixel LCD, and this product is a 128*160 pixel LCD, so some processing has been done on the display: the display starts from the second pixel in the horizontal direction, and the first pixel in the vertical direction. Start to display, so as to ensure that the position corresponding to the RAM in the LCD is consistent with the actual position when displayed.
The LCD supports 12-bit, 16-bit and 18-bit input color formats per pixel, namely RGB444, RGB565, RGB666 three color formats, this routine uses RGB565 color format, which is also a commonly used RGB format
Framebuffer uses a video output device to drive a video display device from a memory buffer containing complete frame data. Simply put, a memory area is used to store the display content, and the display content can be changed by changing the data in the memory.
There is an open source project on github: fbcp-ili9341. Compared with other fbcp projects, this project uses partial refresh and DMA to achieve a speed of up to 60fps
Note: The script will replace the corresponding /boot/config.txt and /etc/rc.local and restart, if the user needs, please back up the relevant files in advance.
We have carried out the low-level encapsulation, if you need to know the internal implementation can go to the corresponding directory to check, for the reason that the hardware platform and the internal implementation are different
2.We use Dev libraries by default. If you need to change to BCM2835 or WiringPi libraries ,please open RaspberryPi\c\Makefile and modify lines 13-15 as follows:
If you need to draw pictures, or display Chinese and English characters, we provide some basic functions here about some graphics processing in the directory RaspberryPi\c\lib\GUI\GUI_Paint.c(.h).
Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and image center mirror respectively.
Set points of the display position and color in the buffer: here is the core GUI function, processing points display position and color in the buffer.
The fill color of a certain window in the image buffer: the image buffer part of the window filled with a certain color, usually used to fresh the screen into blank, often used for time display, fresh the last second of the screen.
Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.
Write Ascii character: In the image buffer, use (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.
Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, you can choose Ascii visual character library, font foreground color, font background color.
Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose character font, font foreground color, font background color of the GB2312 encoding
Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.
Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.;
2. The module_init() function is automatically called in the INIT () initializer on the LCD, but the module_exit() function needs to be called by itself
Python has an image library PIL official library link, it do not need to write code from the logical layer like C, can directly call to the image library for image processing. The following will take 1.54inch LCD as an example, we provide a brief description for the demo.
The first parameter defines the color depth of the image, which is defined as "1" to indicate the bitmap of one-bit depth. The second parameter is a tuple that defines the width and height of the image. The third parameter defines the default color of the buffer, which is defined as "WHITE".
The first argument is a tuple of four elements. (20,10) is the coordinate value in the upper left corner of the rectangle, and (70,60) is the coordinate value in the lower right corner of the rectangle. Fill =" WHITE" means BLACK inside, and outline="BLACK" means the color of the outline is black.
Draw an inscribed circle in the square, the first parameter is a tuple of 4 elements, with (150, 15) as the upper left corner vertex of the square, (190, 55) as the lower right corner vertex of the square, specifying the level median line of the rectangular frame is the angle of 0 degrees, the second parameter indicates the starting angle, the third parameter indicates the ending angle, and fill = 0 indicates that the the color of the line is white.
The first parameter is the coordination of the enclosing rectangle. The second and third parameters are the beginning and end degrees of the circle. The fourth parameter is the fill color of the circle.
The first parameter is a tuple of 2 elements, with (40, 50) as the left vertex, the font is Font2, and the fill is the font color. You can directly make fill = "WHITE", because the regular color value is already defined Well, of course, you can also use fill = (128,255,128), the parentheses correspond to the values of the three RGB colors so that you can precisely control the color you want. The second sentence shows Micro Snow Electronics, using Font3, the font color is white.
The demo is developed based on the HAL library. Download the demo, find the STM32 program file directory, and open the LCD_demo.uvprojx in the STM32\STM32F103RBT6\MDK-ARM directory to check the program.
Open main.c, you can see all the test programs, remove the comments in front of the test programs on the corresponding screen, and recompile and download.
For the screen, if you need to draw pictures, display Chinese and English characters, display pictures, etc., you can use the upper application to do, and we provide some basic functions here about some graphics processing in the directory STM32\STM32F103RB\User\GUI_DEV\GUI_Paint.c(.h)
Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and about image center mirror respectively.
Image buffer part of the window filling color: the image buffer part of the window filled with a certain color, generally as a window whitewashing function, often used for time display, whitewashing on a second
Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.
Write Ascii character: In the image buffer, at (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.
Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, can choose Ascii visual character library, font foreground color, font background color.
Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose GB2312 encoding character font, font foreground color, font background color.
Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.
Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.
DEV_Config.cpp(.h): It is the hardware interface definition, which encapsulates the read and write pin levels, SPI transmission data, and pin initialization;
image.cpp(.h): is the image data, which can convert any BMP image into a 16-bit true color image array through Img2Lcd (downloadable in the development data).
The hardware interface is defined in the two files DEV_Config.cpp(.h), and functions such as read and write pin level, delay, and SPI transmission are encapsulated.
For the screen, if you need to draw pictures, display Chinese and English characters, display pictures, etc., you can use the upper application to do, and we provide some basic functions here about some graphics processing in the directory GUI_Paint.c(.h)
Mirror: indicates the image mirroring mode. MIRROR_NONE, MIRROR_HORIZONTAL, MIRROR_VERTICAL, MIRROR_ORIGIN correspond to no mirror, horizontal mirror, vertical mirror, and about image center mirror respectively.
Draw circle: In the image buffer, draw a circle of Radius with (X_Center Y_Center) as the center. You can choose the color, the width of the line, and whether to fill the inside of the circle.
Write Ascii character: In the image buffer, at (Xstart Ystart) as the left vertex, write an Ascii character, you can select Ascii visual character library, font foreground color, font background color.
Write English string: In the image buffer, use (Xstart Ystart) as the left vertex, write a string of English characters, can choose Ascii visual character library, font foreground color, font background color.
Write Chinese string: in the image buffer, use (Xstart Ystart) as the left vertex, write a string of Chinese characters, you can choose GB2312 encoding character font, font foreground color, font background color.
Write numbers: In the image buffer,use (Xstart Ystart) as the left vertex, write a string of numbers, you can choose Ascii visual character library, font foreground color, font background color.
Write numbers with decimals: at (Xstart Ystart) as the left vertex, write a string of numbers with decimals, you can choose Ascii code visual character font, font foreground color, font background color
void Paint_DrawFloatNum(UWORD Xpoint, UWORD Ypoint, double Nummber, UBYTE Decimal_Point, sFONT* Font, UWORD Color_Foreground, UWORD Color_Background);
Display time: in the image buffer,use (Xstart Ystart) as the left vertex, display time,you can choose Ascii visual character font, font foreground color, font background color.
We have used Liquid Crystal Displays in the DroneBot Workshop many times before, but the one we are working with today has a bit of a twist – it’s a circle! Perfect for creating electronic gauges and special effects.
LCD, or Liquid Crystal Displays, are great choices for many applications. They aren’t that power-hungry, they are available in monochrome or full-color models, and they are available in all shapes and sizes.
Today we will see how to use this display with both an Arduino and an ESP32. We will also use a pair of them to make some rather spooky animated eyeballs!
Waveshare actually has several round LCD modules, I chose the 1.28-inch model as it was readily available on Amazon. You could probably perform the same experiments using a different module, although you may require a different driver.
There are also some additional connections to the display. One of them, DC, sets the display into either Data or Command mode. Another, BL, is a control for the display’s backlight.
Another difference is simply with the labeling on the display. There are two pins, one labeled SDA and the other labeled SCL. At a glance, you would assume that this is an I2C device, but it isn’t, it’s SPI just like the Waveshare device.
This display can be used for the experiments we will be doing with the ESP32, as that is a 3.3-volt logic microcontroller. You would need to use a voltage level converter if you wanted to use one of these with an Arduino Uno.
The Arduino Uno is arguably the most common microcontroller on the planet, certainly for experiments it is. However, it is also quite old and compared to more modern devices its 16-MHz clock is pretty slow.
The Waveshare device comes with a cable for use with the display. Unfortunately, it only has female ends, which would be excellent for a Raspberry Pi (which is also supported) but not too handy for an Arduino Uno. I used short breadboard jumper wires to convert the ends into male ones suitable for the Arduino.
Once you have everything hooked up, you can start coding for the display. There are a few ways to do this, one of them is to grab the sample code thatWaveshare provides on their Wiki.
The Waveshare Wiki does provide some information about the display and a bit of sample code for a few common controllers. It’s a reasonable support page, unfortunately, it is the only support that Waveshare provides(I would have liked to see more examples and a tutorial, but I guess I’m spoiled by Adafruit and Sparkfun LOL).
Open the Arduino folder. Inside you’ll find quite a few folders, one for each display size that Waveshare supports. As I’m using the 1.28-inch model, I selected theLCD_1inch28folder.
Once you do that, you can open your Arduino IDE and then navigate to that folder. Inside the folder, there is a sketch file namedLCD_1inch28.inowhich you will want to open.
When you open the sketch, you’ll be greeted by an error message in your Arduino IDE. The error is that two of the files included in the sketch contain unrecognized characters. The IDE offers the suggestion of fixing these with the “Fix Encoder & Reload” function (in the Tools menu), but that won’t work.
You can see from the code that after loading some libraries we initialize the display, set its backlight level (you can use PWM on the BL pin to set the level), and paint a new image. We then proceed to draw lines and strings onto the display.
Unfortunately, Waveshare doesn’t offer documentation for this, but you can gather quite a bit of information by reading theLCD_Driver.cppfile, where the functions are somewhat documented.
This library is an extension of the Adafruit GFX library, which itself is one of the most popular display libraries around. Because of this, there isextensive documentation for this libraryavailable from Adafruit. This makes the library an excellent choice for those who want to write their own applications.
As with the Waveshare sample, this file just prints shapes and text to the display. It is quite an easy sketch to understand, especially with the Adafruit documentation.
The sketch finishes by printing some bizarre text on the display. The text is an excerpt from The Hitchhiker’s Guide to the Galaxy by Douglas Adams, and it’s a sample of Vogon poetry, which is considered to be the third-worst in the Galaxy!
Here is the hookup for the ESP32 and the GC9A01 display. As with most ESP32 hookup diagrams, it is important to use the correct GPIO numbers instead of physical pins. The diagram shows the WROVER, so if you are using a different module you’ll need to consult its documentation to ensure that you hook it up properly.
The TFT_eSPI library is ideal for this, and several other, displays. You can install it through your Arduino IDE Library Manager, just search for “TFT_eSPI”.
There is a lot of demo code included with the library. Some of it is intended for other display sizes, but there are a few that you can use with your circular display.
To test out the display, you can use theColour_Test sketch, found inside the Test and Diagnostic menu item inside the library samples. While this sketch was not made for this display, it is a good way to confirm that you have everything hooked up and configured properly.
A great demo code sample is theAnimated_dialsketch, which is found inside theSpritesmenu item. This demonstration code will produce a “dial” indicator on the display, along with some simulated “data” (really just a random number generator).
In order to run this sketch, you’ll need to install another library. Install theTjpeg_DecoderLibrary from Library Manager. Once you do, the sketch will compile, and you can upload it to your ESP32.
The first thing we need to do is to hook up a second display. To do this, you connect every wire in parallel with the first display, except for the CS (chip select) line.
You can also hook up some optional components to manually control the two “eyeballs”. You’ll need an analog joystick and a couple of momentary contact, normally open pushbutton switches.
The Animated Eyes sketch can be found within the sample files for the TFT_eSPI library, under the “generic” folder. Assuming that you have wired up the second GC9A01 display, you’ll want to use theAnimated_Eyes_2sketch.
The GC9A01 LCD module is a 1.28-inch round display that is useful for instrumentation and other similar projects. Today we will learn how to use this display with an Arduino Uno and an ESP32.
The TFT module is the heart of this product -- it contains all the subsystems that are required to make an image show up. Starting with one of the most obvious features; the LCD screen is a glass panel with small little cells of liquid crystal (LC) material that can be shifted from opaque to clear with an electronic signal (more on how LCDs work). For each of the 128x160 pixels in the screen there are three LC cells and each cell has either a red, green, or blue filter in it to color the light. A pixel gets colored when white light from the LED backlight passes through the filtered cells in varying amounts.
The amount of light passed through is controlled by the signal applied to the liquid crystal cells, but the sheer number of pins and complexity of those signals is totally impractical to control directly with a microcontroller. Fortunately some really smart cookies created a dedicated driver Integrated Circuit (IC) that stores pixel data and puts it on the screen for us. Connections to the driver, as well as the backlight, are broken out along a flexible flat printed circuit (FPC) cable - and that"s where we take over.
The FPC connector is convenient for two reasons. First, it"s extremely simple to (re)connect the display to the breakout board. Second, production of this product is made easier because all soldering can be done in our normal surface mount process.
To disconnect the TFT module just flip up the black locking bar with a finger or pair of tweezers and then gently pull the cable straight out from the connector. To put the cable back in, first make sure that the polarity indicators on the cable (1, 40) match up with those on the board and that the black locking bar is flipped up. Next push the cable in evenly for about 2mm.
⚡PLEASE NOTE: Pay attention to the direction of the connector cable. Reconnecting the cable upside down could cause shorts since the FPC connector has contacts on both the top and bottom.
The microSD card holder is there to relieve your microcontroller"s poor memory due to having to store hundreds of images of cats, or really whatever you want to keep there. The SD card is connected to the same SPI bus as the display, which in turn keeps the required pin count low.
Out of the box, the TFT will come with a large backing PCB that makes it easy to securely mount the display in a project. If you need a more flexible solution you can remove the display module, snap off half the backing board, and then re-insert the display module. When this is done you"ll be left with the bare minimum frame around the display to more seamlessly integrate with your project.
The pinout of this breakout includes the standard SPI interfaces for both the TFT and the microSD card as well as a few specialty pins. You can power the breakout with either 5V or 3.3V thanks to the onboard voltage regulator and level shifter.
D/C : This is a special signal found in many display controllers. When it is high the incoming data is interpreted as data as opposed to commands when it is low.
Recently, I had the idea to make a digital picture frame—one of these kinds which load images from SD cards and show each image for some time. I was remembering myself that I already own a small TFT display, the KMR-1.8 SPI, that works out of the box with an Arduino Uno. When I digged up my KMR-1.8 SPI, I realized that it has also an in-built SD card reader. Moreover, I looked up the Internet and found ready-to-use libraries for the in-built SD card reader as well as showing images on the TFT display. For these reasons, I thought making such an digital picture frame will turn out very easy.
When I started to implement my first lines of codes and started to connect my Arduino Uno to the KMR-1.8 SPI, I ran into two major problems. First, the colors of my image file did not match to the colors displayed by the KMR-1.8 (red and blue were interchanged). Second, my first prototypes stopped to work after about 5 minutes. The application started to freeze and showed the same image forever instead of displaying the next image after a chosen time.
I did some research on the Internet and I found out that many people ran into similar problems. The second problem seemed to be caused by some memory leaks in the code. Nevertheless, I did not came across any example code that worked out of the box for my setup. Therefore, I want to share how I made it work.
There exists various versions of so-called “1.8 TFT displays” from different manufacturers. Not all of them are 100% compatible to each other. Therefore, if you own a TFT display and want to use my tutorial to make it work, please check if your TFT display really matches the version I used in this tutorial:
The source code relies on three header files (and libraries): SPI.h (Link), SD.h (Link) and TFT.h (Link). Please make sure that all of them are correctly installed before trying out my source code (In Arduino IDE: Tools -> Manage Libraries…).
In the introduction of this blog post, I mentioned that I came across two major problems: the colors red and blue were interchanged and my early Arduino programs started to freeze after some time. Luckily, I was able to fix all issues. The following source code works perfect on my setup. My “digital picture frame” does not require to be restarted after some time (my long-term test lasted about two weeks—and no restart was necessary).
I overcame the first problem by not using the default initialization method (“TFTscreen.begin();”) of the TFT library. Instead, I looked up whats inside the “begin”-method. I found a method called “initR” which has a parameter that allows to perform the initialization for a specific chip. Here, the parameter value “INITR_BLACKTAB” worked for me as the colors were then shown correctly. In addition, I call the method “setRotation” with parameter value “1” in order to be conform to the default initialization method. In the end, the code for the setting up the TFT library object looks like this:// ...
I solved the second problem (application freezes after some time) by avoiding any possible memory leak, i.e. to “free” every bit of memory that was reserved before as soon as it is not needed anymore. Therefore, you will find a lot of “close”-method calls as well as some weird string handling. When I wrote the code, I thought I could simplify a few things. However, the memory leak problems came back. So, the code might look weird but it works :)
The code looks for image files (*.BMP) on the SD card and shows each image for 60 seconds. You can change the display time by setting “DELAY_IMAGE_SWAP” to a new value.
Important Note: The image files on the SD card must be stored as BMP with a resolution of 160x128 pixels (width x height). Moreover, long file names and special characters must be avoided.
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