tft display vs capacitive touchscreen supplier

Touchscreens have changed the way people expect to interact with their devices. When it comes to smartphones and tablets, touch is the way to go. Even handheld game consoles, laptops, and car navigation systems are moving towards touch. Manufacturers of these devices need to give their respective consumers the responsiveness these consumers are looking for. Selecting the right TFT-LCD display to use for different devices is important.

For touch-sensitive displays, two types of technologies are used: resistive and capacitive. The main difference is in how they respond to touch. Mobile phone comparison site Omio indicates that resistive technology is more accurate but capacitive technology is more responsive.

To elaborate on that, resistive touchscreens allow input from fingers and non-finger objects, like a stylus. A stylus has a smaller point than a finger and makes interaction on a resistive screen more accurate. This makes the technology suitable for devices whose applications require high accuracy, like sketching and pinpoint games. Mobile devices that use a stylus typically have resistive touchscreens.

Capacitive touchscreens, on the other hand, offer more responsiveness with better optical clarity and multi-touch performance. They detect more complex finger gestures. These qualities are shown to be more important for general interaction so it’s more dominant in smartphones and tablets, as well as in other devices with small to medium screen sizes.

As you can see, capacitive screens get general usage while resistive screens cater to more specific applications. With this, TFT-LCD module manufacturers, like Microtips Technology, focus on continuously improving capacitive screen technology.

Electronic Design states that many technological advances can be used to integrate touch sensors directly into the display. In some, manufacturers stack-up the touch sensors and integrate the controller with the display driver ICs. These advances allowed thinner and smarter capacitive touchscreens – a trend that you see in many devices today. For example, Windows phones originally worked exclusively with resistive touchscreen technology but later on moved over to capacitive. If the continuous development of capacitive touchscreen technology becomes successful, these screens may soon have abilities they don’t possess at the moment, such as hover support, non-finger support, and many more.

Take your product to the next level with a capacitive touch screen LCD by Displaytech. Our PCAP (projected capacitive) touch screen technology is a premium alternative to a resistive touchscreen. We offer capacitive touchscreens for our 2.8-inch, 3.5-inch, 4.3-inch, 5-inch and 7-inch TFT LCD displays.

Capacitive touch technology allows for an enhanced product user interface since it supports gestures and proximity sensing. Unlike resistive touch screens which rely on pressure, capacitive touch responds to an electric current and can handle multi-finger touch points. This means that capacitive touchscreens can be used with your bare finger and it supports gestures such as pinch-to-zoom or swipe.

Capacitive touchscreen TFT LCDs are available in 2.8", 3.5", 4.3", 5.0", 7.0", and 10.1" diagonal sizes. Capacitive touch TFTs offer excellent contrast and clarity, have a built-in I2C interface, excellent dragging performance, and accept multi-point inputs, also known as multi-touch.

Capacitance screen and resistance screen refer to the transparent and very thin touch film on the surface of mobile phone LCD screen. If that film belongs to capacitive touch layer, then such LCD screen is called capacitive screen; otherwise it is called resistance screen; the same LCD screen can be made into capacitive screen, also can be made into resistance screen. So what"s the difference between capacitive touch screen and TFT LCD screen?

Capacitive touch screen is not a real screen, but a component installed on the top of the LCD screen. The capacitive screen is a transparent toughened glass in appearance.

Capacitive touch screen is a kind of touch screen. It is transparent like glass, it does not display any content and does not emit light. Its function is to perceive user"s touch operation.

TFT screen is the real screen. TFT is one of the most widely used materials for LCD display, which is mainly used in low and middle-end display field, and is widely used in mobile phones. TFT LCD screen is a thin film transistor LCD screen. It is a kind of display screen. It has no touch sensing function and can only be used to display images.

Current mobile phones usually use both screens at the same time. They overlap up and down. TFT LCD screen is responsible for displaying images, while capacitive touch screen is responsible for perceiving user operation. This is the origin of "inner screen" and "outer screen".

What"s the difference between capacitive touch screen and TFT LCD screen? Do you understand? Sidico Technology Co., Ltd. is engaged in the research, production and sales of 8.8 inch strip LCD screen and industrial LCD screen. It provides TFT LCD screen, customized LCD screen and excellent strip LCD screen manufacturer for industrial LCD screen.

If you want to buy a new monitor, you might wonder what kind of display technologies I should choose. In today’s market, there are two main types of computer monitors: TFT LCD monitors & IPS monitors.

The word TFT means Thin Film Transistor. It is the technology that is used in LCD displays.  We have additional resources if you would like to learn more about what is a TFT Display. This type of LCDs is also categorically referred to as an active-matrix LCD.

These LCDs can hold back some pixels while using other pixels so the LCD screen will be using a very minimum amount of energy to function (to modify the liquid crystal molecules between two electrodes). TFT LCDs have capacitors and transistors. These two elements play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy while still generating vibrant, consistent images.

Industry nomenclature: TFT LCD panels or TFT screens can also be referred to as TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology.

IPS (in-plane-switching) technology is like an improvement on the traditional TFT LCD display module in the sense that it has the same basic structure, but has more enhanced features and more widespread usability.

Both TFT display and IPS display are active-matrix displays, neither can’t emit light on their own like OLED displays and have to be used with a back-light of white bright light to generate the picture. Newer panels utilize LED backlight (light-emitting diodes) to generate their light hence utilizing less power and requiring less depth by design. Neither TFT display nor IPS display can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to produce the color consumers see. If you use a magnifier to inspect your monitor, you will see RGB color in each pixel. With an on/off switch and different level of brightness RGB, we can get many colors.

Winner. IPS TFT screens have around 0.3 milliseconds response time while TN TFT screens responds around 10 milliseconds which makes the latter unsuitable for gaming

Winner. the images that IPS displays create are much more pristine and original than that of the TFT screen. IPS displays do this by making the pixels function in a parallel way. Because of such placing, the pixels can reflect light in a better way, and because of that, you get a better image within the display.

As the display screen made with IPS technology is mostly wide-set, it ensures that the aspect ratio of the screen would be wider. This ensures better visibility and a more realistic viewing experience with a stable effect.

Winner. While the TFT LCD has around 15% more power consumption vs IPS LCD, IPS has a lower transmittance which forces IPS displays to consume more power via backlights. TFT LCD helps battery life.

Normally, high-end products, such as Apple Mac computer monitors and Samsung mobile phones, generally use IPS panels. Some high-end TV and mobile phones even use AMOLED (Active Matrix Organic Light Emitting Diodes) displays. This cutting edge technology provides even better color reproduction, clear image quality, better color gamut, less power consumption when compared to LCD technology.

What you need to choose is AMOLED for your TV and mobile phones instead of PMOLED. If you have budget leftover, you can also add touch screen functionality as most of the touch nowadays uses PCAP (Projective Capacitive) touch panel.

This kind of touch technology was first introduced by Steve Jobs in the first-generation iPhone. Of course, a TFT LCD display can always meet the basic needs at the most efficient price. An IPS display can make your monitor standing out.

ER-TFT043A2-3 is 480x272 dots 4.3" color tft lcd module display with driver IC ST7282 and optional capacitive touch panel with controller and connector,optional 4-wire resistive touch panel with connector,superior display quality,wide view angle and easily controlled by MCU such as 8051, PIC, AVR, ARDUINO,ARM and Raspberry PI .

It can be used in any embedded systems,car,mp4,gps,industrial device,security and hand-held equipment which requires display in high quality and colorful image.It supports rgb interface. FPC with zif connector is easily to assemble or remove.Of course, we wouldn"t just leave you with a datasheet and a "good luck!".Here is the link for 4.3"TFT Touch Shield with Libraries, Examples.Schematic Diagram for Arduino Due,Mega 2560,Uno and 8051 Microcontroller Development Board&Kit.

RV013Z1P-300-26 is a small size square 1.3 inch LCD display panel, the interface and brightness acceptable for customized, It is a transmissive type display operating in the normal white. This TFT-LCD has a 1.3 inch diagonally measured active area with QVGA resolutions (240 horizontal by 240 vertical pixel array).

A2: The products can be widely applied to the fields of HMI, Handheld Terminals, Medical Equipment, Instruments and Apparatus, Smart Home Equipment, Shopping Machine, Vehicle Display and AOI, etc.

Capacitive touch screens are control displays that utilise the electrical properties of the human body as input. When a finger (or specialised input device, such as stylus) comes in contact with the display it detects when and where on the display the user touches it. As a result capacitive displays can receive accurate input from very light touches.

Capacitive touch screens are built with a thin layer of conductive material, such as copper or Indium Tin Oxide (ITO), printed onto the underside of the display"s insulating outer layer. When a finger touches the screen, a small electrical charge is drawn to the point of contact, which effectively becomes a functioning capacitor. The resulting change in the electrostatic field is then measured to pinpoint where the contact took place.

Capacitive touch screen technology comes in two key types – projective and surface. With surface capacitance, the more basic of the two technologies, only one side of the insulator is coated with the conductive layer. In contrast, projected capacitance makes use of a matrix of rows and columns of conductive material on one or two layers. This grid pattern allows for superior accuracy and multi-touch functionality.

Capacitive touchscreens are constantly evolving, becoming thinner with progressively more vibrant and sharper images with each development. GTK can even offer fine-tuned capacitive sensors that work with heavy duty gloves. However, capacitive touch technology is not without its rivals; read more about how resistive touchscreens compare on our Capacitive Touch vs Resistive Touch page.

GTK are recognised as specialist TFT capacitive touchscreen suppliers and can help with different applications for a variety of markets - contact us today to see how we can help.

The term ‘TFT LCD’ is a combination of two short forms are ‘TFT’ and ‘LCD’. ‘TFT’ translates to ‘Thin Film Transistor’. ‘LCD’ translates to ‘Liquid Crystal Display’. LCD is a technology used in display devices. LCD allows devices to be thinner than the devices using CRTs (Cathode Ray Tubes). TFT is a type of LCD-flat panel screen that uses one to four transistors. These transistors control the pixels. Another name given to these is Active-Matrix LCD. One of their advantages is that they are much faster and brighter. TFT is capable of displaying thousands of high-contrast color pixels. STONE TECH provides a wide variety of TFT LCD displays.

In medical fields, TFT displays can be used where a human-computer interactive environment is required. Common examples include printing, payments, and inquiry, etc.

Certain devices or machines are required to measure physical parameters. Although voltage and current can be displayed on a simple LCD display. Displays that include multiple parameters such as humidity, temperatures, etc. along with voltage and current can use TFT displays.

Modern-day instruments require a high degree of precision. The higher the precision the better the instrument. TFT displays are used in these instruments to provide a user-friendly display to the user.

In an era where many “manufacturers” simply resell touch screens from low-cost suppliers or outsource manufacturing to third parties, Reshine is a true Capacitive touch&Resistive touch display OEM manufacturer with 12 years of experience. Reshine Display (HK) Technology Co., Limited is a branch of Shenzhen Ruixiang Digital Technology Co., Ltd., which is a high-tech enterprise established in 2007, located in Longhua District, Shenzhen.

We are a leading designer and manufacturer of touch screens, and we have rich experiences in medical & industrial & home automation& products supply.Reshine"s mission is to be the most successful touch screen display supplier in the markets it serves.

The company has a total construction area of 4,000 square meters, with a monthly production capacity of 500,000 pieces, a production staff of 150-200 people, 5 R&D engineers, and 15 quality control personnel with 5-10 years of experience in the touch screen industry, The factory has introduced brand touch&display production equipment from the United States, Japan, South Korea, Taiwan, and a hundred-level purification workshop to ensure that the screens meet the requirements of production equipment and environment.

Ais not a real display screen, but a component that is mounted above the LCD screen. The capacitive touch panel is a transparent tempered glass in appearance.

A capacitive touch panel is a touch panel that is transparent like glass and does not display anything or emit light.Thecapacitive touch panelfunction is to sense the user"s touch operation.

The TFT screen is the real display screen. TFT is the most widely used liquid crystal display material.The TFT LCD screen is a thin film transistor liquid crystal screen, which is a display screen, and has no function of sensing touch, and can only be used to display an image.

In the current display screen, two types of screens, a capacitive touch panel, and a, are usually used at the same time, and the two are vertically overlapped, and the TFT LCD panel is responsible for displaying images, and the capacitive touch screen is responsible for sensing user operations. It is the origin of "internal screen" and "outer screen".

tft display (Liquid crystal display) are made of liquid crystals that form digital images made visible through ambient light or through LED backlight. LCDs are used in the place of other displays that are less efficient such as cathode ray tubes (CRTs) and have become the most popular tft display type on the market.

Tft display enable metal and position detection without having to physically contact the metal object. They offer a wide range of applications in robotics, rail, material handling, aerospace, military, as well as heavy machinery. Choose from different tft display types, from the shielded versions that have electromagnetic fields concatenated in the front and unshielded applications that allow wider sensing distances. Whether you want to use your sensors for industrial purposes or source for your brand, there is a wide selection of wholesale tftcd to choose from that will suit different applications.

Browse cutting-edge tft display on Alibaba.com at reasonable prices. tft display in varying display size and resolution are accessible on the site. The merchandise are useful in automotive, medical, and industrial screen displays. tft display having multiple interface types and display technology are in stock. tft display on Alibaba.com have high resolution and luminance to display precise details. They have a capacitive touch for convenient use. They can show multiple characters per line. tft display can be manufactured to suit smaller wearable devices or large projectors. They can be integrated with smart home systems for face recognition and office equipment. They feature multiple interfacing types like MPU or RS232.. are sturdy, thanks to a toughened glass structure with a considerable operating temperature range. The life span of tft display stretches up to several thousand working hours.tft display support TFT.

DS040HSD24T-003 is a 4.0 inch TFT TRANSMISSIVE LCD Display, it applies to 4.0” color TFT-LCD panel. The 4.0 inch color TFT-LCD panel is designed for video door phone, smart home, GPS, camcorder, digital camera application, industrial equipment device and other electronic products which require high quality flat panel displays, excellent visual effect. This module follows RoHS.

DS043CTC40T-021 is a 4.3 inch TFT TRANSMISSIVE LCD Display, it applies to 4.3” color TFT-LCD panel. The 4.3inch color TFT-LCD panel is designed for video door phone, smart home, GPS, camcorder, digital camera application, industrial equipment device and other electronic products which require high quality flat panel displays,excellent visual effect. This module follows RoHS.

DISEN is a global leading LCD panel supplier and specialized in producing TFT LCD Panel, including Color TFT LCD, Touch panel screen, special design TFT Display, Original BOE LCD display and bar type TFT Display. Disen’s Color TFT displays are available in various resolutions and offers a wide product range of small to medium-sized and parts of big size TFT-LCD modules from 0.96” to 32". We have got the certificated of quality ISO9001 and environment ISO14001 and automobile quality IATF16949 and medical device ISO13485 certificated. As a leader manufacturer in the display module market, Disen will continue to dedicate the research & development, design, of new technology of LCD, TFT.

These wide viewing angle Small Format TFT LCDs with optional touch are industrial grade and cost competitive. Therefore these products are a popular display choice to integrate in many projects for example for use in ticket vending machines (TVMs) and other custom projects.

Using only high-tech factories that we partner with, we provide clients with the service of designing liquid crystal display panel (LCD) and liquid crystal display module(LCM), and is committed to the customized service, R&D, sales, after-sales service of display products. Our factories have hundreds of engineers focusing on creating the highest quality displays including monochrome LCD (TN, STN), colour LCD (CSTN and TFT), Custom LCD’s, LCD module (both COG* and COB*) which are widely used in mobile phones and many other applications.

Our state of the art factory produces High Resolution TFT glass panel cells, has TN, HTN, STN and TFT technologies for LCD panels. The Factory has class 1000 clean rooms, high accuracy bonding, pre bonding and heat seal machinery, many production lines specifically for TFT production, OCA and OCF bonding machines,  In-House LCD glass cleansing process, output thousands of pieces per month.

Touchscreen overlay cover glass only available (so you do not have to purchase the display)These displays can come with: touchscreen components, touchscreen overlays, industrial touch screen,Wide LCDs, LED TFTs, and TFT Colour displays.

Other options are: LCD drivers, LVDS Touchscreen displays, automotive LCD Display, TFT high resolution screens, TFT LCD capacitive touchscreens, TFT capacitive touchscreens, high brightness LCDs, Letterbox Displays, small VGA Displays, LCD panel without backlights,Variations of our Small Format TFT LCDs include: TFT Display touchscreens, TFT IPS Display, monochrome displays, TFT or LCD, embedded components, LCD components, TFT Drivers, industrial range of Displays,

CDS also offers industrial TFT LCDs,Our displays are used in: touch screen vending machines, automotive touch screen displays, vending machine display panel, Touch screen vending, TFT Automotive, LCD Dislay panel kits, Touch screen TFT monitors, LCD Display components, LCD Screen components,  and POS LCD Displays.As you can see from the tables above we have sizes including:  8.8 inches, 4.3 inch LCD Display, 10.1″ TFT LCD,  3.5 inch LCD Display, 4.3 inch display, 3.5 inch TFT LCD Display, 4.3″ screen, 7 inch LCD panel, 3 inch LCD Displays, and 4.3″ TFT LCDs as well as other small LCD Display screens.We have options on and equivalents to the following displays and TFT panel manufacturers:  Raystar, Kingtech LCD, Digital View, OLED modules, OLED products, Powertip LCD Displays, Data Vision LCD, LG TFT Display, Tianma NLT, Powertip Displays, Mitsubishi LCD Displays, DMC components, Kyocera LCDs, NLT Technologies Ltd, Sharp LCD TFT modules, LCD manufacturers in the USA, PMOLED Displays, innolux display corp, Industrial touchscreens, A Grade TFT LCD Displays, Panoramic TFT Displays, Samsung TFT Displays, Touchscreen components, Transparent TFT Displays, Touchscreen components,  TFT LCD controllers, as well as other TFT LCD manufacturers and Liquid crystal Display manufacturers.

CDS offers the widest range of displays and touchscreens including Abon touchscreens, Ampire LCD distributor, alternative Prisma interface baord supplier including Prisma iiia, Solomon Goldentek, Panasonic TFT, Winmate display, USB IO, and Apollo monitors

Our range includes AMOLED, circular displays, circular monitors, circular screens, circular TFT screens, round displays, Round TFT LCD displays, TFT AMOLEDs, TFT and IPS, TFT display interface microcontroller, TFT LCD or AMOLED, TFT LCD super AMOLED, WXGA TFT Displays, and WXGA TFT screens

As well as large format displays CDS also offers DSI TFT Display, large monochrome LCD displays, mono displays, mono OLEDC displays, mono TFT LCDs, monochrome displays, PCT Touchscreens, projected capacitive touch PCT technology, sq monitors and squid IDS.

CDS added a number of additional controller boards nd accessories which include TFT adaptor boards, TFT boards, TFT display controller boards, USB c LCD controller, USB touch kit, resistive touch screen, TFT accessories com, LCD controller board, LCD controller board USB c, LCD controller board, HDMI to MiPi DSI board, HDMI to MiPi DSI bridge, HDMI to MiPi LCD controller board, EDP adaptor bard, elite C microcontroller, Displaylink DL 3000 .

Whether it be bar type LCDs or any of CDS display solutions or many TFT displays we can help with comparing mipi dsi vs lvds interfces or mipi to edp wch can include use on pos shelf displays and rgb epaper for example.

In chapter 7, we made use of the segmented LCD display on the Wonder Gecko Starter Kit through the use of a pre-built LCD library and driver when designing the user interface for the sprinkler timer. That made things easy for us, and we didn’t really need to dwell on how the driver worked. In this chapter, we will dig into some of those details so that we can connect the EFM32 to any kind of display we choose.

The display we will be using for this chapter is the Adafruit 2.8” 240x320 TFT LCD Capacitive Touch screen, shown below. We will interface with it over SPI for transferring image data and I2C for reading the touch interface. We will learn how to interface with it with our own drivers and build our own simple graphics libraries, as well.

Segmented Display: We have already worked with the segmented LCD display in chapter 7, also known as a character display. In such a display, there are a fixed matrix of LCD segments that are preconfigured in hardware to convey specific information. They are not flexible enough to display an image, but they don’t require many pins on the MCU and are easier to program. For example, the number “9” can be formed on such a display with as few as 6 signals.

Graphics Display: A graphics display has a matrix of pixels, each of which are individually addressable. Therefore, in order to display the number “9”, it can require many more pixels than the segmented display. The benefit of a graphic display is that the letter “9” can be in any font we choose, and better yet, we can display any shapes we choose. The drawback to a graphical display is that it takes an enormous number of signals to drive all of those pixels. For the display used in this chapter, which has a resolution of 240 pixels wide by 320 pixels tall, there are 76,800 individually-addressable pixels, and each of those are made up of red, green, and blue components for each pixel.

In order to cut down on the number of signals required to drive such a display, each pixel is driven one at a time in a column-and-row scan technique. This scanning only requires 240 + 320 wires for our chosen display, which are toggled on or off many times per second, even for a static image. The pixels do not hold their color information for very long, and therefore they require periodic refreshes.

Graphical display screens have many different technologies, from passive-matrix Liquid Crystal Display (LCD) or active-matrix Thin Film Transistor (TFT) LCD, Light Emitting Diode (LED), or Organic LED (OLED). Display technology is not the focus of this chapter. No matter which technology you choose, you will still need to understand the topics of this chapter in order to display your images.

A display is a layered device, with each part customizable by the manufacturer. The display is constructed on top of a circuit board which houses the connector and any controller chips that are necessary. The backlight is located on top of the circuit board, with the pixel matrix sitting on top of the backlight. The touch sensor is optional and is located at the top of the stackup.

The LCD pixel matrix is the heart of the display. This part is responsible for displaying the image and, in the case of LCD displays, it will either allow or prevent light from a backlight to pass through. In the case of LED displays, the pixel matrix produces the light and forms the image in one step. No matter the process, the pixel matrix is comprised of an array of pixels in height and width of a certain color depth that make up the display. For the display used in this chapter, the color depth is 18 bits, consisting of 6 bits each for the red/blue/green components of a pixel. That means that the information required to paint the screen one time is 240 bits wide x 320 bits tall x 18 bits of color = 172,800 bytes. That’s a lot of data, and it is more data than we can hold in the RAM of the Wonder Gecko MCU. Therefore, it will require some intelligent code to drive the display or an external memory buffer to store the image data.

The backlight is necessary for TFT LCD displays to allow the display to be seen. Without a backlight, a color TFT LCD will show no image. A monochrome LCD is a little different, since the segments can be seen if they are in the “on” state. The brightness of an LCD screen is sometimes controlled by applying a Pulse Width Modulated (PWM) signal to a pin (or pins) that controls the LED backlight. This is exactly what we have already done in the last chapter to dim an LED.

A display driver chip is used to drive 76,800 signals by rotating through all horizontal and vertical scan lines many times per second. This component is an optional component of the display, and if it is present, it dramatically reduces work for the MCU to display (and continue to display) an image on the screen.

A frame buffer is a block of RAM that holds all of the color information for every pixel (172 kB for this display) that is used to paint a single image (or “frame”) to the display. This buffer is required to exist somewhere in the system because it is used by the display driver chip to refresh the LCD image many times per second.

A touch interface is an optional component and will often have its own control chip or control signals that are separate from the display driver chip.

A capacitive touch screen requires no physical contact between the user and the sensor. Therefore, the sensor can be placed beneath hardened glass or plastic. A valid touch is formed by the change in capacitance measured on the sensor. A human finger can change the capacitance of this sensor, whereas a plastic stylus will not produce a change in capacitance. The capacitive touch screen used in this chapter uses a controller that communicates via the I2C interface.

The type of architecture used in our display (and system) has a huge impact on how we will write our software code, as well as how well our display will perform. You cannot assume that any model of MCU can sufficiently drive any type of display. You must be aware of the architecture details and MCU pinout so that you can determine the best type of display for your needs.

In a general sense, all display architectures require the above control blocks. The display contains a number of scan lines (depending on the resolution) and an image driver that must continually feed the scan control circuitry with pixel data, even for a static image. The pixel control allows light to pass for an instant, and then the pixel goes dark again. If the scan control circuitry were stopped, the display would turn dark, as all pixels would be turned off. Therefore, the image driver needs a frame buffer of memory somewhere in the system to fetch the pixel data that is needed for every scan. The application fills the frame buffer as new drawing operations change what is to be displayed on the screen.

In the RGB interface mode, the MCU acts as the image driver. This means that it must constantly drive data to the display, refreshing all 320 x 240 pixels many times per second. You can imagine the amount of work that would require of your MCU. If the frame buffer is too big to fit in the MCU RAM, an external memory chip must be used. The frame buffer can be attached to the MCU via serial interfaces such as I2C or SPI for static images such as device menus, but must utilize a parallel interface in order to keep up with the demands of full motion video. The External Bus Interface (EBI) can be used with external memory for maximum speed and ease of use, as long as your particular model of EFM32 supports it. EBI extends the RAM of your EFM32 and allows you to address external memory as if it resides within the RAM address space of the EFM32 itself.

When a display has an integrated device driver chip and frame buffer (such as the Ilitek ILI9341 used in this chapter), the MCU doesn’t have to perform all of the constant refreshing of the display; it only sends data to the driver chip when the image changes. This enables the MCU to offload all of that work to stay focused on the application at hand rather than driving the display.

These driver chips usually offer both parallel and serial interfaces to receive image data from the MCU. Parallel interfaces are required if the display will be used for full-motion video and require 8 or more data interface pins. Serial interfaces can be used for static images like device menus and only require 3 or 4 interface data pins.

There are displays available on the market (such as the EVE series from FTDI) which go well beyond a display driver chip. They contain the ability to create graphical shapes such as lines, rectangles, and circles, as well as device controls such as windows, sliders, and buttons. These displays can even offer an integrated touch controller and audio capabilities. The displays communicate over I2C or SPI, and the data that is sent is similar to a software Application Programming Interface (API). The specs of such displays define the commands that the controller chip accepts, and the application software simply communicates each graphic primitive one-by-one to the display to paint the appropriate picture on the screen. These types of displays can be easier to program, but are not the focus of this chapter.

Since graphic displays are complex devices, the code that runs them should be broken up into parts that deal with only one part of the problem. This is known as a software stack.

At the top of the stack is the application software. Application software is focused on providing a solution to the end user, such as the content of menus, fetching images from flash storage, responding to user input, and generally deciding what to do next. Application software should not have to be bogged down with the simple task of how to write a snippet of text to the screen, or the exact details of how to display an image. These things should be handled further down the stack to keep your application code simple.

In order for your application code to stay focused on its mission, your graphics library should provide useful methods to do common things, such as paint the screen with a color, display text, create lines or shapes, and display graphic images. We will learn how to build a very simple graphics library of our own as part of this chapter.

At the bottom of the software stack, the device driver is the necessary code that customizes your graphics library for your particular display device architecture and physical hardware connection. (Note that a software device driver is not the same thing as the device driver chip on the physical display.) Graphics libraries are flexible, and can be adapted to many different display architectures, but they need to be configured for your display architecture and MCU. The device driver provides this customization, providing the display’s resolution and color depth, mapping the data bus for the display to GPIO pins on your MCU and setting up the memory for the frame buffer (if applicable).