The MXT1296M1T can reconfigure its touch control and receive channels to accommodate any screen format, from 1:1 to 5:1, including the 8:3 format commonly used in automotive applications. This feature allows customers to efficiently utilize the number of available touch channels without requiring a larger and more expensive touch controller. Customers can save development and validation time and resources by reusing a common printed circuit board design to ensure compatibility with touch sensors of different formats. The MXT1296M1T is the first on the market to allow reconfiguration of the sensing sensor channel via parameters. This configuration does not require firmware modification, reducing design risk and accelerating time to market.
“Touchscreens have become very popular in automotive user interfaces, and car manufacturers use various formats to suit their interior design and emphasize their brand identity,” said Clayton Pillion, director of the user interface business unit at Microchip Technology. “As the number one supplier of automotive touchscreen controllers, we know that products with advanced diagnostic capabilities provide a significant advantage to customers who incorporate unique features into their designs and increase the functional safety requirements of ISO 26262.”.
Microchip's new maXTouch touchscreen controller offers two communication interfaces that operate simultaneously, enabling a bridgeless connection to the back channel of the LVDS video link for touch input and a connection to a local microcontroller. The bridgeless topology reduces touch latency to improve the user experience.
It also ensures full compatibility with the maXTouch software driver, available for the main operating systems used in automotive applications, including Linux®,Android™, and QNX®.When connected to a suitable local microcontroller, the second interface offers:
- A redundant connection to the central unit via a CAN bus or 10BASE-T1S automotive Ethernet link in order to increase functional safety at the system level
- Local access and control of maXTouch touchscreen controller functions, such as capacitive key reports, real-time touch sensor diagnostics, and raw data for external and customized post-processing
- Wireless and secure firmware upgrade capability via Microchip's TrustAnchor100 auxiliary chip
The MXT1296M1T incorporates several functional safety features to continuously verify the operational integrity of the touch controller and one of the connected touch sensors. The FMEDA (Failure Modes, Effects, and Diagnostic Analysis) and functional safety manual greatly enhance the user experience when designing, developing, and certifying a system for ASIL-B (Automotive Safety Integrity Level B) applications in accordance with the ISO 26262 standard.
The MXT1296M1T enables high-resolution transmission waveform control to reduce RF emissions and prevent interference with car radios or RFID systems. The increasing size of in-car displays leads to greater RF emissions generated by capacitive projection touch technology. Emission limits vary in amplitude, frequency, and bandwidth depending on the major car manufacturer. The MXT1296M1T uses an integrated 64-level digital-to-analog converter (DAC) to accurately generate the transmission line waveform. This allows designers to precisely control the frequency response and optimize harmonic emissions to meet the limits defined by each OEM.
Development tools
The configuration and adjustment of the MXT1296M1T are supported by the latest version of the integrated development environment (IDE) maXTouch Studio.
The available development kits include:
- ATEVK-MXT1296M1T-A: Powerful evaluation kit consisting of a development board with USB connection, 12.3”/8:3 format and 1.1mm OGS (One Glass Solution) touch screen, and auxiliary boards with touch keys for mutual and self-capacity
- ATMXT1296M1T-I2C-PCB: Development board for connecting to client touch sensors
Availability
The MXT1296M1T is now available in production. The ISO 26262 FMEDA and Safety Functional Manual will be available in the first quarter of 2022. For more information, contact a Microchip sales representative or authorized distributor, or visit the Microchip website.
The TrustAnchor100 is now available in production. For more information, contact a Microchip sales representative or authorized distributor, or visit the Microchip website.
