In recent years, electronic products have been iterated continuously and consumer products become more and more intelligent; meanwhile, much more attention has been paid to green development and environmental protection. Under such circumstances, the concept of paperless application was put forward to meet the needs of digital era, and the digitizer tablet is one of the most representative products. A digitizer tablet is a computer input device that consists of an electronic tablet and an electromagnetic induction touch pen. Compared with traditional drawing tools, the digitizer tablet can be connected to computer through USB or BLE and directly transfer data to the computer to display the hand-drawing effect, which greatly improves the operation efficiency and graphic quality. Nowadays, it is commonly used for electronic signature in hospitals, banks and telecommunications, as well as the education industry and creative designing.

Based on the principle of electromagnetic induction, the digitizer tablet works according to the magnetic field changes generated during the operation of electromagnetic induction touch pen and induction antenna under the panel. The pen is the signal transmitter, and electromagnetic induction board in the host is the signal receiver. When the pen is close to the induction board, the magnetic flux changes; then it is amplified by a precision amplifier and sent to A/D conversion circuit for signal acquisition; after A/D conversion, it is read by MCU, and then processed and calculated through MCU algorithm to obtain the coordinates of contact points, and finally displayed on PC or LCD screen.

In the past, the tablet was usually operated with fingers, but it was difficult to render fine strokes due to large friction of fingers. In addition, there are limitations in the specifications and functions of digitizer tablet. Therefore, the electromagnetic induction touch pen is developed to serve as a medium for the panel and users, which can render fine strokes, react quickly and display the coordinates of contact points, graphics and stroke traces. When the user draws, writes or depicts on the digitizer tablet, the MCU can quickly track movements of the touch pen, so that stroke traces can be completely displayed on PC or LCD screen.

ARTERY AT32 MCU uses a 32-bit ARM® Cortex®-M4/M0+ core featured with high performance, high precision and high stability, which is especially suitable for handwriting recognition and conforms to customer expectations of handwriting. It has three low-power modes, i.e., Sleep mode, Deepsleep mode and Standby mode, which allows the product to maintain proper current consumption in long-term operation. For example, ARTERY’s value-line AT32F415 MCUs and wireless BLE AT32WB415 MCUs have a maximum frequency of 150 MHz and support up to 256 KB Flash and 32 KB SRAM, and are designed with USART/SPI/I2C/OTG/CAN standard communication interfaces to help developers connect it to wireless modules, sensors and other expanded features, so as to meet application requirements.

Application features of AT32F415 MCUs and AT32WB415 MCUs

● Rich peripherals, integrated with UART, SPI, I2C, USB OTG and CAN standard communication interfaces, for wide range of product applications;
● Internal12-bit independent ADC, with 2Msps sampling rate and up to 8 sampling high-speed channels to improve the measured position coordinate resolution;
● Power supply of 2.6 V~3.6 V, helps to keep measured value constant and improve reliability;
● Use BLE5.0 SoC core and support Bluetooth 2.4 GHz, with Rx sensitivity up to -97 dBm, Tx value being within -20 dBm~+4 dBm, and effective transmission range exceeding 30 m, to realize high recognition accuracy and control function (for AT32WB415 MCUs only);
● Operating temperature range of -40~105 °C, guaranteeing long-term stable operation in adverse environment;
● Provided with development software and tools, which is easy for configuration and operation.