802.15.4 is an open standard for low-power, low-data-rate radio in the unlicensed 2.4GHz band, and is widely used in communication and networking applications such as smart energy metering, home automation, security and monitoring equipment, and remote controls. The ZigBee™ Alliance has specified IEEE 802.15.4 as the radio platform for the industry-standard ZigBee protocol, which is popular in applications such as sensor networking and automatic meter reading.
ST’s new 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 IEEE802.15.4 MAC. Other well known protocols include ZigBee RF4CE for radio-frequency remote controls or 6LoWPAN for wireless embedded Internet solutions. Software support for the STM32W family includes libraries for the latest ZigBee PRO specification, as well as ZigBee RF4CE, and the IEEE 802.15.4 MAC.
The new devices combine the benefits of a best-in-class radio platform with the added performance, flexibility and scalability of the STM32 microcontroller architecture. The STM32 portfolio is the industry’s leading microcontroller product range featuring the advanced 32-bit ARM Cortex-M3 processor, and it was the first to eliminate all obstacles to broad 32-bit usage in embedded applications. Advantages such as high processing performance, advanced power management and high integration, as well as real-time behavior, have attracted large numbers of developers to the STM32 platform, worldwide.
Joining this successful product line, the STM32W family benefits from compatibility with other STM32 variants and also leverages the STM32 development ecosystem. Developers also benefit from best-in-class code density, which is at least 20% better than other architectures thanks to the efficiency of the Cortex-M3 core.
The STM32W is a true SoC combining best-in-class IEEE 802.15.4 RF performance as well as 32-bit processing. The devices can transmit up to 7dBm output power and support up to 107dB link budget, achieve up to –100dBm receiver sensitivity, and allow coexistence with nearby Wi-Fi and Bluetooth networks, which also operate in the 2.4GHz frequency band.
Performance highlights of the STM32W family include low power consumption, drawing as little as 27mA in receive mode and 31mA in transmit mode, and implementing a 1µA Deep-Sleep mode to aid power management. 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 with Schmitt-trigger inputs. Single-voltage operation from 2.1V to 3.6V simplifies design, while high integration also saves external components. 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.
The smart combination of a best-in-class 2.4GHz radio and powerful 32-bit machine brings outstanding network system performance and associated low-power operation enhancing battery life time.