Microchip Ramps Security on Touchscreen Controllers for EV Chargers

Touchscreens and their controllers used in outdoor EV charging stations must withstand adverse weather conditions and offer a reliable way to transfer customer data to the operational backend. For instance, moisture may condense on a touchscreen surface and cause inaccurate readings that are sent to the touchscreen controller.

Additionally, “false touches” can happen if significant water droplets or moisture condense on a touchscreen surface. Microchip's new touchscreen controllers, the ATMXT2952TD-C2UEN, can compensate for these effects and eliminate the possibility of false touches, even with up to 22 mm of water condensation.

 

Condensation on touchscreens can adversely affect performance. Image used courtesy of Microchip

 

The device also features various other noise-suppression features to compensate for situations arising from multi-touch interactions. These include a lens-bend algorithm to adjust for warping in the touchscreen display, touch suppression to mitigate effects from unwanted screen touches, and self-capacitance sensing to respond to both bare finger touches and glove usage.

The product brief mentions that the device can support up to a 21-inch touchscreen display and has automatic touch sensor diagnostics, which can be reported using a dedicated output pin.   

Another concern with outdoor touchscreens besides the weather is vandalism. Consequently, the ATMXT2952TD 2.0 can be used with IK10-standard, 6-mm glass displays. An IK10 display meets standard IEC 62262 level ten, which indicates the highest level of protection against external mechanical impacts. 

 

 

The 2.0 Family Enhances Security Features 

The new MXT2952TD 2.0 touchscreen controllers mitigate the threat of malicious actors gaining access to sensitive customer information by encrypting touch information and cryptographically authenticating software updates. The new 2.0 family allows customers to integrate secure credit card payment services into a touchscreen-based EV charging station.

The 2.0 family allows customers to run firmware directly on the controller, eliminating the chance of man-in-the-middle attacks that can occur when, for example, an RFID reader and touchscreen controller are on different physical PCBs.

 

Man-in-the-middle attacks are a particular vulnerability of complex electronic systems. Image used courtesy of Invicti

 

A man-in-the-middle attack allows a malicious actor to access personal information by intercepting communication between two elements. Using the 2.0 family, however, firmware can run directly on the controller, eliminating the need for separate RFID and controller boards. In one scenario, the user may simply enter a secure PIN on the touchscreen and authenticate directly for payment.