Skyworks和Ember ZigBee前端模塊參考設計

Ember公司的EM250是單片ZigBee解決方案,集成了2.4GHz, IEEE 802.15.4兼容的收發器以及16位XAP2b微處理器,128KB閃存和5KB SRAM存儲器與基于ZigBee應用的外設.收發器允許和IEEE 802.11g 與藍牙共存,接收靈敏度為-99dBm,輸出功率為+3dBm,主要用于建筑物自動化和控制,家庭自動化控制,家庭娛樂控制以及財產跟蹤等.本文介紹了EM250的主要特性,方框圖和應用電路圖與所用材料清單.此外還介紹了采用EM250和Skyworks公司的SKY65335和SKY65337的ZigBee前端模塊參考設計的電路圖和材料清單(BOM).

The EM250 is a single-chip solution that integrates a 2.4GHz, IEEE 802.15.4-compliant transceiver with a 16-bit XAP2b microprocessor. It contains integrated Flash and RAM memory and peripherals of use to designers of ZigBee-based applications.

The transceiver utilizes an efficient architecture that exceeds the dynamic range requirements imposed by the IEEE 802.15.4-2003 standard by over 15dB. The integrated receive channel filtering allows for co-existence with other communication standards in the 2.4GHz spectrum such as IEEE 802.11g 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 by a further 3dB.
The XAP2b microprocessor is a power-optimized core integrated in the EM250. It supports two different modes of operation—System Mode and Application Mode. The EmberZNet stack runs in System Mode with full access to all areas of the chip. Application code runs in Application Mode with limited access to the EM250 resources; this allows for the scheduling of events by the application developer while preventing modification of restricted areas of memory and registers. This architecture results in increased stability and reliability of deployed solutions.

The EM250 has 128kB of embedded Flash memory and 5kB of integrated RAM for data and program storage.
The EM250 software stack employs an effective wear-leveling algorithm in order to optimize the lifetime of the embedded Flash.

To maintain the strict timing requirements imposed by ZigBee and the IEEE 802.15.4-2003 standard, the EM250 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. In addition, the EM250 allows for true MAC level debugging by integrating the Packet Trace Interface.

To support user-defined applications, a number of peripherals such as GPIO, UART, SPI, I2C, ADC, and generalpurpose timers are integrated. Also, an integrated voltage regulator, power-on-reset circuitry, sleep timer, and low-power sleep modes are available. The deep sleep mode draws less than 1μA, allowing products to achieve long battery life.

Finally, the EM250 utilizes the non-intrusive SIF module for powerful software debugging and programming of the XAP2b microcontroller.

EM250主要特性:
Integrated 2.4GHz, IEEE 802.15.4-compliant transceiver:
Robust RX filtering allows co-existence with IEEE 802.11g and Bluetooth devices
- 99dBm RX sensitivity (1% PER, 20byte packet)
+3dBm nominal output power
Increased radio performance mode (boost mode) gives - 100dBm sensitivity and + 5dBm
transmit power
Integrated VCO and loop filter
Integrated IEEE 802.15.4 PHY and lower MAC with DMA
Integrated hardware support for Packet Trace Interface for InSight Development Environment
Provides integrated RC oscillator for low power operation
Supports optional 32.768kHz crystal oscillator for higher accuracy needs
16-bit XAP2b microprocessor
Integrated memory:
128kB of Flash
5kB of SRAM
Configurable memory protection scheme
Two sleep modes:
Processor idle
Deep sleep—1.0μA (1.5μA with optional 32.768kHz oscillator enabled)
Seventeen GPIO pins with alternate functions
Two Serial Controllers with DMA
SC1: I2C master, SPI master + UART
SC2: I2C master, SPI master/slave
Two 16-bit general-purpose timers; one 16-bit sleep timer
Watchdog timer and power-on-reset circuitry
Non-intrusive debug interface (SIF)
Integrated AES encryption accelerator
Integrated ADC module first-order, sigmadelta converter with 12-bit resolution
Integrated 1.8V voltage regulator
EM250主要應用:
Target applications for the EM250 include:
Building automation and control
Home automation and control
Home entertainment control
Asset tracking



圖1.EM250方框圖



圖2.EM250典型應用電路