The sphere of applications that can exploit high-resolution, touchscreen display technologies keeps expanding thanks to the evolution of easy-to-integrate display modules designed for embedded use.
Integrating a display into your embedded system can be a tricky task. To help you keep pace, a variety of modular displays are available today in all shapes and sizes. These solutions are providing high-resolution screens with touchscreen capabilities and rich feature sets.
Over the past 12 months, display module vendors have rolled out a variety of new solutions—in sizes large and small—that feature enhanced performance, new levels of ruggedness and rich sets of interface support. Support MCU interfaces and improved e-paper displays are also part of the latest display trends.
Perhaps the most significant trend in this technology space over the past year is toward features and tools to make it easier for embedded developers to add a display to their design and craft the GUI software to go with it. Today’s crop of display modules either make such integration easy, or provide complete pre-integrated display-computer subsystems.
Exemplifying these trends, among the most recent offerings from 4D Systems is its uLCD-90DT/DCT series with 9.0″ Diablo16 Integrated Display Modules designed specifically to cater to the growing demand for physically large displays. The display is part of the microLCD range of modules designed and manufactured by 4D Systems. Visually, the 9.0″ is designed to provide a pleasing aesthetic experience, with 800×480 resolution and RGB 65K true-to-life colors. This generous size makes the unit well suited across a range of projects that require increased display space, says the company.
The ULCD-90DCT module features a 9.0″ color TFT LCD display, with resistive touch (DT) or capacitive touch (DCT) (Figure 1). It is powered by the 4D Systems Diablo16 graphics processor, which offers an array of functionality and options suited for both embedded engineers and makers. Other features include touch detection, microSD memory storage, GPIO and communications, along with multiple millisecond resolution timers and audio generation.
The display module is 100% compatible with the 4D Systems’ Workshop4 IDE as well as other development environments. This provides system developers with a wealth of options for programming and for controlling their systems. Workshop4 provides very fast, drag-and-drop style programming that drastically cuts down development and allows for faster prototyping and time to market, according to 4D Systems. Anything designed to run on other 4D Systems display modules featuring Picaso or Diablo16 graphic processors can be run seamlessly, with little or no required modifications.
TINY DISPLAY WITH SPI
Displays for space-constrained embedded systems must be able to work seamlessly with simple MCU-kinds of interfaces. Along just those lines, in April Newhaven Display released its 2.4″ premium line TFTs. The company enhanced its 2.4″ TFT displays with SPI to allow for more flexibility in embedded designs and faster data transfer than I2C.
These displays deliver crisp images at 240×320 resolution with a powerful LED backlight, plus a built-in controller for easy communication with any MCU, says the company (Figure 2 top). The 3.3V LCDs have a 3-line/4-line SPI interface and an FFC (flexible flat cable) connector. The unit supports MVA viewing angles (70 degrees) and boasts a high-brightness white LED backlight (850cd/ m2). These transmissive displays support wide temperature operation from -20°C to 70°C and are RoHS compliant.
In March, Newhaven Display rolled out its 4.3″ IPS TFT line of displays, with multiple versions to choose from. The displays are available in HDMI, mountable and EVE2 versions with the option for capacitive touch screens (Figure 2 bottom). According to the company, the IPS displays provide wider viewing angles and more accurate color reproduction for the most premium, high quality images on any TFT. The 4.3″ IPS TFTs deliver images in a crisp 800×480 resolution—that’s almost double the resolution of standard TFT LCDs, says Newhaven Display.
IPS (in-plane switching) technology acts on the liquid crystals inside an LCD so when voltage is applied, the liquid crystal rotates in parallel (or in-plane) allowing the light to pass through instead of turning upright. This behavior of the crystals greatly improves many viewing aspects of the display. Compared to regular TN panels, IPS is superior in color, viewing angles and these TFTs can even handle direct sunlight due to their high brightness.
The company has developed a full line of 4.3″ TFT displays with IPS technology to enhance the viewing experience of embedded applications. The 4.3″ IPS TFT is the standard edition and provides the same powerful, reliable performance with the upgraded visuals and viewing angles of in-plane switching and the option for a capacitive touch screen. The 4.3″ HDMI IPS TFT features the plug-and-play accessibility of an integrated Texas Instruments (TI) controller built in to the IPS TFT. These HDMI TFTs work seamlessly with Raspberry Pi to enable embedded developers to get started faster with Windows and Linux.
Newhaven Displays 4.3″ Mountable IPS TFT lets you safely secure your IPS TFT to any application. These mountable displays are rack height ready and compatible with standard M3 screws, so there’s no guesswork when it comes to installation. And finally, the 4.3″ EVE2 IPS TFT provides capacitive touch interaction powered by Bridgetek’s video engine and open source software.
COMMAND CONTROLLED TFT
For embedded systems displays, part of the challenge is not just the product specs themselves. It’s also about features that make it easier to do system integration and GUI development. An example along those lines is the most recent offering from Noritake. Noritake’s GTWV050C3A00PA is a command-controlled touch TFT module designed to facilitate quick embedded GUI development and reduce system costs with powerful built-in commands.
The GTWV050C3A00PA module consists of a 5″ high brightness TFT panel (800×480-pixel resolution), a 5VDC single power supply, a FLETAS-brand metallized projective capacitive touch (MPCT) panel and all the necessary drive circuitry (Figure 3). The mounted FLETAS touch panel has high touch sensitivity that can operate accurately in demanding environments. Touch works with gloves and up to a 5mm acrylic overlay (with 0.5mm air-gap).
The GTWV050C3A00PA is based on Noritake VFD command sets. It has a combination of Noritake’s GU3000 ASCII-based text commands, full-color image commands and scalable-font compatibility. The module can work with a wide range of low- and high-end microcontrollers using industry standard serial interfaces (Async., I2C, SPI and USB).
The GTWV050C3A00PA integrates a high-quality PCB design intended for industrial applications and a high brightness 1,000cd/ m2 5″ TFT panel. The display has adaptive sensitivity that works with gloved hands, water droplets and thick overlays. On-board flash memory available to store many images and fonts.
E-PAPER DISPLAY SOLUTIONS
Electronic paper displays (EPD) continue to evolve, with a growing range of suitable products designed for embedded needs. For example, in March, Pervasive Displays (PDi) made its full range of Aurora black and white e-paper, or E-ink, electrophoretic displays (EPD) available (Figure 4). These chip-on-glass (COG) front plane laminate (FPL) displays make use of the latest driving waveform technology to produce sharp images in a thin design that leaves plenty of room for an application’s electronic control circuitry and battery, says PDi.
EPDs have expanded the options for applications requiring monochrome displays, thanks to their bi-stable functionality. Only updating the display’s image requires power, allowing total power consumption to be kept to an absolute minimum. This makes them ideal for applications where the content of the display changes irregularly, such as digital signs, retail spaces, office automation, building navigation, reusable badges and healthcare. Such solutions can also be battery powered, allowing them to be installed in locations that lack alternative locally installed power sources, such as shelving, on doors and windows, or devices that are not fixed in place.
In order to provide a low-cost option for solutions using EPDs, some products in the range integrate their own timing controller (Tcon) and booster circuitry. This helps to minimize the external circuitry required to interface with the display to reduce the total bill of materials (BOM) and simplify the software programming required. For full flexibility, EPDs with an external Tcon are also available but may require an optional boost circuit.
The Aurora Ma (V230) range of EPDs support operation over the -25°C to 10°C temperature range, the Aurora Mb (V231) EPDs 0°C to 50°C, and Aurora -25 (V430) EPDs the -20°C to 50°C range, while providing resolutions of between 100 and 140 dots-per-inch (DPI). A one-time programming (OTP) option also allows predefined images to be recalled without the need for long data transfers from a host CPU. For a 3.0V supply voltage, a updating a typical image requires less then 5mA for a 212×104-pixel ESD, taking around 2 seconds.
SLIM PANEL PC
Panel PCs are a category of display systems that are meant to be mounted on a factory wall or on the side of an industrial machine. They’re also well suited for transportation systems like railway user interfaces. Rather than simply being a display, panel PCs embed complete single board computing functionality, providing a complete embedded solution.
In an example along those lines, in February Axiomtek announced the GOT115-319, a 15″ fanless touch panel computer. It is powered by the Intel Celeron processor N3350 or Intel Pentium processor N4200 with the Intel GFX controller onboard. The GOT115-319 has an XGA TFT LCD display with 1024×768 resolution and a choice of a projected capacitive multi-touch or resistive touch touchscreen (Figure 5). It also has 300 nits of brightness and an LED backlight. It is feature-rich, flexible and rugged for use in multimedia kiosks or as a human machine interface (HMI) for smart manufacturing and retail applications.
The ultra-slim GOT115-319 features a thickness of only 50mm for use in space-constrained environments, says Axiomtek. Its I/Os include two GbE LAN ports, one RS-232 port, one RS-232/422/485 port with RI/5V/12V selectable by BIOS, two USB 3.0 ports, two USB 2.0 ports and one Line-out. Other features include one power button, one remote power switch and one screw-type connector for power.
The GOT115-319 has an easily accessible external switch for AT/ATX mode selection, and built-in speakers and microphone for multimedia applications. For expandability, the touch panel computer has one full-size PCI Express Mini Card slot and one M.2 Key E slot for RFID and wireless network module installation. It is equipped with one 204 pin DDR3L-1600 SO-DIMM with up to 8GB of memory.
The GOT115-319 also offers one 2.5″ SATA HDD/SSD, one mSATA and one MicroSD card for storage. For reliable operation in harsh environments, it features an IP65-rated front bezel, wide operating temperature range of 0°C to +50°C and vibration endurance for up to 2G. The thin touch panel PC can be mounted on a panel mount, wall mount, VESA arm or desktop stand.
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • AUGUST 2020 #361 – Get a PDF of the issueSponsor this Article
Jeff served as Editor-in-Chief for both LinuxGizmos.com and its sister publication, Circuit Cellar magazine 6/2017—3/2022. In nearly three decades of covering the embedded electronics and computing industry, Jeff has also held senior editorial positions at EE Times, Computer Design, Electronic Design, Embedded Systems Development, and COTS Journal. His knowledge spans a broad range of electronics and computing topics, including CPUs, MCUs, memory, storage, graphics, power supplies, software development, and real-time OSes.