Renesas Technology America Inc. has introduced a 16-bit H8 MCU-based evaluation platform that demonstrates an LCD direct-drive capability for supporting QVGA-size thin-film transistor (TFT) and super-twisted nematic display (STN) LCD panels. Because it can directly operate LCD panels, the company says the board eliminates the need for a separate LCD controller, decreasing overall system cost and shortening time to market.
“This solution essentially provides engineers with an easy path to drive and display complex images on TFT-LCD panels,” explains Ritesh Tyagi, director of the LSI business unit at San Jose, CA, U.S.–based Renesas. “It was clear that the majority of product developers do not have expertise in driving LCD panels as well as creating images on the LCD panel.”
The LCD evaluation demo board combines the Renesas H8S/2378 MCU and a graphic software/GUI (graphical user interface) package from Segger Microcontroller Systems. The supported Segger software includes library routines for creating any form of high-quality images on the display. “Demonstrations are running out of the box, with all software source code as well as a software API optimized for LCD applications,” says Tyagi. “This allows customers to jump-start their projects and to incorporate sophisticated graphics on LCD panels at low cost.”
Smooth display of animation and still images on LCD panels can be achieved in real time through the use of a multibus architecture and an on-chip external DMA (direct memory access) controller of the MCU. “By using the two types of buses and the dedicated external DMA controller, the MCU can drive data directly between an external frame buffer and an LCD panel, thus enabling a fast data rate and deterministic operation of images on the LCD display,” Tyagi tells APPLIANCE. “During data transfer, the MCU also synchronizes control signals by using a timer pulse unit (TPU) to ensure real-time operation. These on-chip functions operate LCD panels in a fully time-deterministic way, imposing virtually no overhead on the CPU core. With extra headroom, the MCU is able to perform all other system connection algorithms and functions effectively.”
According to Tyagi, the unique aspect of the platform is that by using a 16-bit MCU, developers can incorporate high-quality LCD panels into their low- to midrange products at a low cost. “Many customers already have high-end products that use high-performance MCUs, but they can often result in higher bill-of-materials cost,” he says. “This is not acceptable for their low- and midend models that need to be developed at much lower cost.”
The cost savings make the MCU-based solution ideal for cost-sensitive appliance applications such as refrigerators, ovens, and thermostats, as well as medical devices and fitness equipment. “Renesas wanted to offer its current customer base as well as new customers a product which allows them to easily and quickly migrate to more-sophisticated TFT-LCD panels,” Tyagi notes.
For example, using a touch-sensitive LCD panel, sophisticated button features can be easily implemented on a microwave oven LCD panel. “Connectivity to the touch screen as well as an analog-to-digital convertor channel operation for sensing analog voltages on the touch-sensitive grid are enabled using the multiple serial interfaces offered by the H8 MCU,” Tyagi explains. “Generally, the display of an oven will be static with a small amount of changes, such as changes in temperature and status. Using the solution, developers can take advantage of the full-scale software development environment to simply implement LCD graphic displays into a wide range of home appliances.”
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