Networked home appliances allow both users and manufacturers to communicate with them via the Internet. For example, users of kitchen ovens can find new recipes online, and manufacturers can implement remote diagnostics or firmware updates over the air. Displays and touch sensors are critical to enabling this functionality in modern appliances. Microchip Technology Inc. today announced that its family of IEC/UL 60730 Class B-certified touchscreen controllers has added two new members, the MXT448UD-HA and MXT640UD-HA. The new product can expand the application range of the B-level product portfolio to more than 10 inches, and is a dedicated solution for larger screen sizes, and customers can also adjust it according to their needs.
In addition to complying with Class B specifications, the new devices are also compliant with IEC61000-4-6 Class A specifications for conducted noise immunity up to 10 Vrms (Class 3 for industrial use). This enables products with touchscreen interfaces to operate in very harsh factory environments where conveyor belts, power lines or assembly machinery may cause electromagnetic interference. Manufacturers of home appliances will benefit from increased reliability and productivity. This is a significant improvement over consumers using unprotected touchscreens on ovens or washing machines, where unprotected power transmission, electric motors and electromagnetic interference from adjacent electrical equipment can lead to unwanted or missed touches.
The new touchscreen controller is also equipped with two serial interfaces (SPI and I²C) that can operate simultaneously, by integrating security functions such as separate communication between the touchscreen controller and the host microprocessor (MPU) and a secure microcontroller (MCU) , allowing for redundancy in the design. Touch events are provided to both processors simultaneously. This unique structure reduces time-to-market and development costs as it allows all safety-critical firmware to be developed on a dedicated safety-certified MCU (mandatory source code review by IEC/UL test labs), Separate from the main processor that runs the device’s graphical user interface (GUI).
“As products add more control through touchscreens, interfaces must work reliably to meet and protect users,” said Clayton Pillion, director of Microchip’s Human Interface Business Unit. We have worked closely with our customers to deliver the first family of functionally safe touch controllers, with strong adoption in scenarios where noise immunity is critical to product success.”
In addition to compliance with IEC standards, the MXT448UD-HA and MXT640UD-HA series support operating temperatures up to 105°C. This is a key requirement for cooktops and ovens where the Human Machine Interface (HMI) system is located close to the heating element.
Microchip provides software to support these new controllers, including maXTouch Studio (development tool) and maXTouch Analyzer (production end-of-line test/inspection tool). In addition, a generic ATEVK-MXT640UD-A Evaluation Kit (EVK) is available. Customers specifically requesting a functional safety version of this evaluation kit for home appliances should contact Microchip.
Availability and Pricing
The two new devices (ATMXT448UD-CCUHA1 and ATMXT640UD-CCUHA1) for home appliances have started mass production, with the ATMXT448UD starting at $2.40 per unit and 10,000 units.
Original Title: Microchip Introduces Family of Capacitive Touchscreen Controllers for the Home Appliances Market for Harsh and Noisy Environments
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