This all-inclusive design ensures that the AVR-IoT Cellular Mini is an ideal platform for developing secure, connected, smart IoT solutions.
The AVR-IoT Cellular Mini development board is a comprehensive hardware platform designed to facilitate the evaluation and development of IoT solutions. This platform integrates the Microchip AVR128DB48 AVR microcontroller, ATECC608B secure element, and the GM02S cellular module, providing a robust foundation for IoT applications. Accompanying the development board is a Truphone SIM card with 150 MB of data, ready for activation, simplifying the setup process.
The AVR-IoT Cellular Mini is a compact and versatile demonstration and development platform, leveraging the AVR® microcontroller architecture and cellular technology. Its design simplifies IoT application development by dividing the task into three primary components: The core components of the design include being intelligent, connected, and secure. The AVR128DB48 microcontroller represents the smart functionality. Connectivity is facilitated through the GM02S cellular module, which comes equipped with an antenna and SIM card. Security is ensured by the ATECC608B secure element. Integrating IoT cellular tracking significantly enhances existing products by adding cellular IoT capabilities. This integration and the streamlined design process, helps reduce development time, accelerating time-to-market. Additionally, the board comes fully tested with all necessary design files and software, ensuring reliability and ease of use.
The board supports various power sources, including a USB port, Li-Ion/LiPo battery, or an external power supply. It features a buck converter for 3.3V with LDO standby mode and an LDO for 1.8V. Additionally, it includes an MCP73830 Li-Ion/LiPo charger and a JST battery connector. The charger limits the charge current to 196 mA, preventing overcharging of small-capacity batteries, and terminates the charge cycle when the current drops below 37 mA or if it exceeds the safety timer of four hours. The AVR128DB48 MCU supports Multi-Voltage I/O (MVIO), with Port C designated for MVIO and powered from VDDIO2 at 1.8V. The MVSYSCFG fuse controls the MCU’s supply state; if set to single-supply mode, all pins in Port C will be tri-stated due to insufficient VDDIO2 supply voltage. The default MVSYSCFG fuse setting is dual-supply mode.
Power to all board components is routed through five cut-straps with 50-mil holes, clearly marked on the silkscreen for current measurement purposes. The system voltage measurement circuit on the board uses the MIC94163 switch and a voltage divider connected to an ADC pin on the AVR128DB48, enabling on-demand measurement while preventing power leakage through the voltage divider. The AVR-IoT Cellular Mini also includes an on-board debugger for programming and debugging. This debugger is a composite USB device featuring multiple interfaces, making it a versatile tool for developers.
Microchip Technolgy has thoroughly tested this reference design, which includes a bill of materials (BOM), schematics, assembly drawing, and printed circuit board (PCB) layout. The company’s website provides additional information about this reference design. To learn more, click here.
