Dalian Dapinjia Group Launches EVB, a Touch Sensing Design Solution Based on Microchip Products
On October 15th, 2021, the leading semiconductor component distributor dedicated to the Asia-Pacific market, General Assembly Holdings, announced that its subsidiary Pinjia has launched a touch-sensing design solution EVB based on Microchip’s ATTINY1616.
Figure 1-Display board diagram of the touch-sensing design solution based on Microchip products by Dalian Dapinjia
Touch sensing is becoming a technological trend. It can be found in household appliances, portable Electronic products, or car control screens. The touch-sensitive design is favored by users due to its beauty and durability. In today’s rapidly changing market, manufacturers urgently need a high-performance touch sensing design to meet market demand. The touch sensing design solution EVB, launched by Dalian Dapinjia based on Microchip ATTINY1616 MCU, can help developers complete the design in a short period of time, thereby seizing the market.
Figure 2-Scenario application diagram of Dalian Dapinjia’s touch sensing design solution based on Microchip products
This solution uses an 8-bit MCU from Microchip-ATTINY1616. With the Atmel Studio development environment, it can easily realize the design of touch buttons, sliders, and scroll wheels. Microchip is a supplier of intelligent, connected and secure embedded control solutions. Its easy-to-use development tools and comprehensive product portfolio enable customers to create optimal designs, thereby reducing risk while reducing overall system costs.
As a touch sensing design, this solution uses the principle of self-capacitance sensing, that is, detecting changes in the sensor capacitance. There is a parasitic capacitance Cp between the Sensor (capacitive buttons and sliders) and the ground. When a touch occurs, a finger capacitance Cf will be formed, and the total capacitance Cs will change at this time. There are two kinds of Microchip capacitive sensing technology, one is based on mTouch? Technology CVD, and the other is QTouch? Technology PTC. The ATTINY1616 chip used this time is equipped with QTouch technology. It can be used for button, slider and scroll wheel design, and provides built-in hardware for capacitive touch measurement. PTC supports mutual capacitance and self-capacitance measurement, without any external components, can provide excellent sensitivity, noise immunity and self-calibration function, and can minimize the workload required for the user to adjust the sensitivity.
Figure 3-Block diagram of the touch sensing design solution based on Microchip products by Dalian Dapinjia
The noise problem is an unavoidable problem with capacitive touch. Both common mode noise and differential mode noise will affect the performance of touch keys. Therefore, designers need to consider noise immunity at the beginning of the design. This scheme can realize the anti-noise design well through hardware design + software debugging. In addition, the solution can also achieve a waterproof design by adding Driven Shield or Driven Shield+.
Core technical advantages:
High signal-to-noise ratio (SNR);
Passed IEC61000 EFT and BCI test.
Water resistant touch function:
The touch interface can be used normally under various environmental conditions (including wet surfaces), without the need to clean or dry hands each time the device is used.
Metal surface touch function, waterproof touch function:
Microchip provides metal surface capacitance (MoC) technology, which supports:
Metal surface: stainless steel or aluminum;
Can be tested through gloves of any thickness;
Support Braille interface.
Low power consumption:
The dedicated hardware on PIC, AVR and SAM devices supports the touch function with the lowest power consumption, and its capacitive sensing current is less than 5μA.
Support mutual capacitance touch sensing, can support multiple keys:
Microchip has optimized and enhanced the method of scanning a large number of buttons in a matrix. Costs can be saved in several ways:
Reduce the number of feed lines and simplify the connection of input and output (flexPCB) ports;
Reduce the number of pins required for touch, making the device cost-effective and occupying less space;
Through Microchip’s unique inherent feed line length compensation, the development time is greatly reduced.
Safety certified touch sensing function:
Microchip provides products (off-the-shelf products and sensor libraries) that have passed the IEC/UL 60730 safety class B standard certification.
Up to 12 self-capacitive keys/36 mutual-capacitive keys can be realized;
Designs such as sliders and rollers can be realized;
Support Driven Shield and Driven Shield+;
With I2C/SPI/UART interface;
There are car-regulated products.