In response to the aging society trend and the promotion of personal health management concepts, various household measuring healthcare instruments provide wireless transmission of health indexes such as blood pressure, blood sugar, temperature, and body fat. In addition to everyday health measuring tools, Bluetooth technology application further expands to dental care and skin care, including Bluetooth toothbrush or personal beauty apparatus. By integrating the Bluetooth pass-through technology and APPs developed by manufacturers, the Bluetooth toothbrush can record personal health indexes, oral health, and brushing habits. In contrast, the beauty apparatus can record the use pattern. This assists the vendor in providing household products and expands the possibility of personalized service to strengthen the connection with the after-sales service.

Bluetooth solution for personal healthcare supplies

Take the electric toothbrush as an example. The NuMicro^® M031BT with Nuvoton Arm^® Cortex^®-M0 can utilize the Bluetooth pass-through to transfer data to APP to achieve differentiated service. Its 12 PWMs of 96 MHz can be used as the motor control to drive and adjust the vibration frequency of the electric toothbrush and control the light to display different use models of the electric toothbrush. With multiple sets of I/O to connect the sensor module, the ADC with a high sampling rate can provide precise voltage measurement to confirm the electric toothbrush's power. The NuMicro® M031BT microcontroller can fulfill these functions mentioned above with a rich built-in peripheral, excellent stimulation control function, and integrated Bluetooth technology.

Diagram of NuMicro^® M031BT to achieve Bluetooth toothbrush application

The NuMicro^® M031BT series of Nuvoton with Arm^® Cortex^®-M0 core provides double module function of BLE 5.0 and 2.4 GHz, transmission power up to +8 dBm for radiofrequency application, fine receiving sensitivity of -92 dBm, and 1 Mb/s or 2 Mb/s transmission rate. It also has outstanding noise cancellation performance in the environment with serious interference of 2.4GHz to increase the communication distance and reliability that meets the smart home's application needs, consumer electronics, and IIoT.

The NuMicro^® M031BT series has an operating frequency of up to 48 MHz with built-in 128 KB Flash and 16 KB SRAM. Its rich peripheral I/O can be configured as USCI of UART, I2C, or SPI, and there are three sets of 6 MHz UART available to support single-wire transmission. Furthermore, with the operating voltage between 1.8V to 3.6V, built-in 32-bit hardware multiplier/divider, and 5 PDMA, the 12-bit ADC with 16-channel and 2 MSPS high sampling rate operating in low-voltage of 1.8V provides precise and rapid performance. At the same time, 12-channel 96 MHz PWM can quickly respond and precisely control the external device.

To protect the developer's intellectual property rights, the NuMicro^® M031BT series embedded an additional SPROM (Security Protection ROM) to save critical codes by providing an independent and safe encryption area. The firmware provided by the design of flash lock bits prevents external access or write protection. Each M031BT has a 96-bit chip with a unique identification (UID) and 128-bit unique customer identification (UCID) to improve the product's confidentiality and code safety significantly.

Compared with the traditional BLE SoC providing a simple integrated peripheral solution, the NuMicro® M031BT series has built-in rich peripheral and excellent stimulation control functions to reduce the PCB size significantly. The QFN48 with a 5mm x 5mm packing area also reduces the difficulty in radiofrequency layout. Moreover, the development of low-power Bluetooth applications becomes easier due to the pass-through sample code of Nuvoton.