MikroElektronika's SPIRIT click carries the STMicroelectronics SP1ML 868 MHz ultra-low-power RF module. The board is designed to use 3.3 V power supply and 3.3 V or 5 V I/O voltage levels. It communicates with the target MCU over UART interface with additional functionality provided by the following pins on the mikroBUS™ line: PWM, RST, CS. It can be used to wirelessly send and receive UART data. SP1ML is based on the SPIRIT1 RF sub-GHz transceiver (with integrated SMPS), STM32L1 microcontroller, integrated filter/balun, and chip antenna. There are two operational modes, command mode and operating mode. The command mode allows module configuration and status interrogation using an extended ‘AT’ style command set. In operating mode, the module serves its primary purpose as a wireless transceiver and uses only 13.5 mA, 2.2 mA in command mode, and even lower in standby with just 1.4 µA. This kind of power consumption makes it ideal for smart devices that send small amounts of data. The module has an integrated antenna and crystal.

The SPIRIT1 is a very low-power RF transceiver intended for RF wireless applications in the sub-1 GHz band. It is designed to operate both in the license-free ISM and SRD frequency bands at 169 MHz, 315 MHz, 433 MHz, 868 MHz, and 915 MHz, but can also be programmed to operate at other additional frequencies in the 300 MHz to 348 MHz, 387 MHz to 470 MHz, and 779 MHz to 956 MHz bands. The air data rate is programmable from 1 kbps to 500 kbps, and the SPIRIT1 can be used in systems with channel spacing of 12.5/25 kHz, complying with the EN 300 220 standard. It uses a very small number of discrete external components and integrates a configurable baseband modem which supports data management, modulation, and demodulation. The data management handles the data in the proprietary fully programmable packet format and also allows the M-Bus standard compliance format (all performance classes).