ST 公司的STM32W108C8是集成了64KB閃存的高性能IEEE 802.15.4無線系統級芯片(SoC),包括有2.4 GHz IEEE 802.15.4兼容的收發器,32位ARM Cortex-M3微處理器,閃存和RAM,以及基于ZigBee的系統外設. 正常情況下的接收靈敏度為-99dBm,輸出功率為+3dBm,能WiFi與藍牙共存,單電源2.1-3.6 V工作,主要用在ZigBee RF4CE遙控和人工接口設備,2.4 Ghz IEEE 802.15.4 MAC網絡,消費類電子設備和簡單的網絡RF控制.本文介紹了STM32W108C8主要特性,方框圖,以及STM32W-SK評估板和STM32W-EXT 擴展板電路圖和相應的材料清單.
The STM32W108C8 is a fully integrated System-on-Chip that includes a 2.4 GHz IEEE 802.15.4-compliant transceiver, a 32-bit ARM?Cortex?M3 microprocessor, Flash memory and RAM, and peripherals of use to designers of ZigBee-based systems.
The transceiver utilizes an efficient architecture that exceeds the dynamic range requirements imposed by the IEEE 802.15.4-2003 standard by over 15 dB. The integrated receive channel filtering allows for robust co-existence with other communication standards in the 2.4 GHz spectrum, such as IEEE 802.11 and Bluetooth. The integrated regulator, VCO, loop filter, and power amplifier keep the external component count low. An optional high performance radio mode (boost mode) is software-selectable to boost dynamic range.
The integrated 32-bit ARM?Cortex?M3 microprocessor is highly optimized for high performance, low power consumption, and efficient memory utilization. Including an integrated MPU, it supports two different modes of operation: Privileged mode and Unprivileged mode. This architecture could be used to separate the networking stack from the application code and prevent unwanted modification of restricted areas of memory and registers resulting in increased stability and reliability of deployed solutions.
The STM32W108C8 has 64 Kbytes of embedded Flash memory and 8 Kbytes of integrated RAM for data and program storage. The STM32W108C8 HAL software employs an effective wear-leveling algorithm that optimizes the lifetime of the embedded Flash.
To maintain the strict timing requirements imposed by the ZigBee and IEEE 802.15.4-2003 standards, the STM32W108C8 integrates a number of MAC functions into the hardware.
The MAC hardware handles automatic ACK transmission and reception, automatic backoff delay, and clear channel assessment for transmission, as well as automatic filtering of received packets. A packet trace interface is also integrated with the MAC, allowing complete, non-intrusive capture of all packets to and from the STM32W108C8.
The STM32W108C8 offers a number of advanced power management features that enable long battery life. A high-frequency internal RC oscillator allows the processor core to begin code execution quickly upon waking. Various deep sleep modes are available with less than 1uA power consumption while retaining RAM contents. To support user-defined applications, on-chip peripherals include UART, SPI, I2C, ADC and general-purpose timers, as well as up to 24 GPIOs. Additionally, an integrated voltage regulator, power-on-reset circuit, and sleep timer are available.

STM32W108C8主要特性:
■ Exceptional radio performance
– 2.4 Ghz IEEE 802.15.4 compliant RF transceiver
– Normal mode link budget up to 102 dB; configurable up to 107 dB
– −99 dBm normal RX sensitivity; configurable to −100 dBm (1% PER, 20 byte packet)
– +3 dB normal mode output power; configurable up to +7 dBm
– Robust WiFi and Bluetooth coexistence
– Worldwide radio compliant reference design (ETSI, ARIB, FCC)
– Low cost bill of material to implement cost effective solutions
■ Low power consumption and advanced management
– Receive current (with CPU): 27 mA
– Transmit current (with CPU, +3 dBm TX): 31 mA
– Low deep sleep current, with retained RAM data and GPIO states: 400/800 nA with/without sleep timer
– Low frequency internal RC oscillator for low-power sleep timing
– High frequency internal RC oscillator for fast (100 μs) processor start-up from sleep
■ Full-featured system-on-chip
– 32-bit ARM® Cortex™-M3 processor
– 64-Kbyte Flash memory, 8-Kbyte RAM
– AES128 encryption accelerator
– Flexible ADC, SPI/UART/I2C serial communications, and general-purpose timers
– 24 highly configurable GPIOs with Schmitt trigger inputs
■ Innovative network and processor debug
– Non-intrusive hardware packet trace
– Serial wire/JTAG interface
– Standard ARM debug capabilities: Flash patch & breakpoint; data watchpoint and trace;instrumentation trace macrocell
■ Application flexibility
– Single voltage operation: 2.1-3.6 V with internal 1.8 V and 1.25 V regulators
– Optional 32.768 kHz crystal for higher timer accuracy
– Low external component count with single 24 MHz crystal
– Support for external power amplifier
– IR generation capable
– Pin and software compatibility with STM32W108xx series
– Small 7x7 mm 48-pin VFQFPN package

STM32W108C8應用:
■ ZigBee RF4CE remote control and human interface devices
■ 2.4 Ghz IEEE 802.15.4 MAC networks
■ Consumer electronics devices
■ Simple network RF control

圖1.STM32W108C8方框圖

STM32無線MCU評估套件包括STM32W-SK評估板和STM32W-EXT 擴展板
STM32W-SK Evaluation kit for STM32 Wireless devices
The STM32W-SK and STM32W-EXT starter and extension kits are easy to use tools for the STM32W108xx microcontrollers. This family of microcontrollers integrates a 32-bit ARM® Cortex™-M3 microprocessor and a 2.4 GHz, IEEE 802.15.4-compliant transceiver. The kits demonstrate how effectively the STM32W108xx can be used in real IEEE 802.15.4 applications. They are suitable for different types of wireless network scenarios such as:
● Remote control and target networks (based on the ZigBee RF4CE protocol stack) used for driving consumer devices such as TVs, set-top boxes, etc.
● Point to point networks (based on a Simplified MAC library) used to address a basic IEEE 802.15.4 communication. This configuration enables customers to develop any protocol stack of their choice.
The STM32W108xx kits provide demonstration applications and documentation which serve as a reference for creating your own applications and re-programming the STM32W108xx microcontroller. You can run the STM32W108xx kits in several ways (remote control/target and point-to-point applications), using the dedicated software libraries (ZigBee RF4CE, and Simplified MAC), as well as a third-party IDE and C compiler (IAR).
Moreover, the STM32W108xx kits provide a set of HAL APIs which allow you to use the kit platform capabilities such as LEDs and serial communication channels (virtual COM through USB).
There are two types of STM32W108xx kit:
● The starter kit (order code: STM32W108B-SK)
● The extension kit (order code: STM32W108C-KEXT)

STM32W-SK評估板
The STM32W108xx starter kit package contains the following hardware components:
● Two STM32W108 application boards (MB851)
● One STM32W108 extension board (MB850)
● One Raisonance STM32-Primer2 tool (STM3210E-PRIMER)
● One J-Link Lite JTAG Flash programmer and debugger
● One mini USB cable
● Four AAA batteries

圖2.STM32無線MCU評估套件外形圖

圖3.STM32W-EXT 擴展板MB850電路圖
MB850材料清單:


圖4.STM32W108應用板MB851電路圖(1)

圖5.STM32W108應用板MB851電路圖(2)
STM32W108應用板MB851材料清單(BOM):