The devices, targeting embedded wireless sensor network applications, exceed the dynamic range requirements imposed by the IEEE 802.15.4 standard by over 15 dB, according to ST. IEEE 802.15.4 is an open standard for low-power, low-data-rate radio and is the radio platform for the ZigBee protocol, popular in applications such as sensor networking and automatic meter reading.
ST says the radio can transmit up to 7dBm output power, achieve up to -100dBm receiver sensitivity and allow co-existence with nearby Wi-Fi and Bluetooth networks, which also operate in the 2.4GHz frequency band.
The STM32W family implements the IEEE 802.15.4 physical (PHY) layer as well as the Media Access Control (MAC) layer, giving developers the flexibility to target ZigBee-compliant specifications or to build any network wireless protocol which interfaces with the standardized 802.15.4 MAC. Special features supporting wireless applications include 8Kbyte SRAM, 128Kbyte flash for code storage, and embedded AES encryption with hardware acceleration.
General-purpose resources include a flexible ADC, an SPI/UART/TWI serial interface, multiple timers, and 24 GPIOs. Single-voltage operation from 2.1V to 3.6V simplifies design, and only a single 24MHz crystal is required (or an optional 32.768kHz crystal for increased timer accuracy). There is also support for an external power amplifier.
Performance benefits include low power consumption-- as little as 27mA in receive mode and 31mA in transmit mode. To aid power management various deep sleep modes are available with less than 1 ?A power consumption while retaining RAM contents.
Software support for the STM32W family includes libraries for the latest ZigBee PRO specification, as well as ZigBee RF4CE for radio-frequency remote controls, and the IEEE 802.15.4 MAC. Developers also benefit from compatibility with other STM32 variants and can leverage the STM32 development ecosystem.
The STM32W family is available in a 6 x 6mm 40-pin QFN package pin-to-pin compatible with the SN260, or a 7 x 7mm 48-pin QFN compatible with the SN250. Pricing begins at $2.90 for quantities over 100,000 units with the ZigBee PRO feature set.