Touchscreen controller supports multiple screen formats

November 30, 2021 // By Christoph Hammerschmidt
Touchscreen controller
The automotive market is demanding ever-larger touchscreens with more flexibility in size and shape. Microchip Technology Inc. presents the maXTouch touchscreen controller for this purpose, which enables automotive developers to implement different and special aspect ratios for touchscreens in vehicles. In addition, the new controller supports functional safety according to ISO 26262.

The MXT1296M1T can reconfigure its driving and receiving touch channels to match the specific display format, from 1:1 to 5:1, including the 8:3 aspect ratio popular in automotive applications. This feature allows customers to take advantage of the number of touch channels available without having to rely on larger and more expensive touch controllers. It also saves additional development and validation time and resources by reusing a common PCB design to support different touch sensor aspect ratios. As an industry first, the MXT1296M1T allows reconfiguration of sensor channels via parameters. These settings do not require a firmware change, enabling lower design risk and faster time-to-market.

The maXTouch touchscreen controller offers two communication interfaces working in parallel, providing a seamless connection to the LVDS video link return channel for touch information and a connection to a local microcontroller (MCU). This seamless topology reduces touch latency and thus improves ease of use. In addition, this topology guarantees full compatibility with the maXTouch software drivers, which are available for all major automotive operating systems such as Linux, Android™ and QNX.

When connected to a suitable local MCU, the second interface provides:

  • A redundancy connection to the main unit via a CAN bus or a 10BASE-T1S automotive Ethernet connection for increased system-level functional safety.
  • Local access and control over maXTouch touchscreen controller functions, such as a capacitive button report, live touch sensor diagnostics, and raw data for external and custom post-processing
  • A secured over-the-air firmware update function with Microchip's TrustAnchor100 companion chip.

The MXT1296M1T includes several functional safety features to permanently verify the integrity of the touch controller operation as well as any of the connected touch sensors. The Failure Modes Effects and Diagnostic Analysis (FMEDA) and Functional Safety Manual provide customers with significant relief when designing, building and certifying a system for Automotive Safety Integrity Level B (ASIL-B) applications to the ISO 26262 standard.

The device enables high-resolution control of the transmit waveform


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