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EM250
the CRC, and provides 4-bit symbols to the baseband. When the final byte has been read and sent to the
baseband, the CRC remainder is read and transmitted.
The MAC resides in RX mode most of the time, and different format and address filters keep non-intended
packets from using excessive RAM buffers, as well as preventing the CPU from being interrupted. When the
reception of a packet begins, the MAC reads 4-bit symbols from the baseband and calculates the CRC. It
assembles the received data for storage in a RAM buffer. A RX MAC DMA provides direct access to the RAM
memory. Once the packet has been received, additional data is appended to the end of the packet in the RAM
buffer space. The appended data provides statistical information on the packet for the software stack.
The primary features of the MAC are:
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CRC generation, appending, and checking
Hardware timers and interrupts to achieve the MAC symbol timing
Automatic preamble, and SFD pre-pended to a TX packet
Address recognition and packet filtering on received packets
Automatic acknowledgement transmission
Automatic transmission of packets from memory
Automatic transmission after backoff time if channel is clear (CCA)
Automatic acknowledgement checking
Time stamping of received and transmitted messages
Attaching packet information to received packets (LQI, RSSI, gain, time stamp, and packet status)
IEEE 802.15.4 timing and slotted/unslotted timing
4.4
4.5
Packet Trace Interface (PTI)
The EM250 integrates a true PHY-level PTI for effective network-level debugging. This two-signal interface
monitors all the PHY TX and RX packets (in a non-intrusive manner) between the MAC and baseband modules.
It is an asynchronous 500kbps interface and cannot be used to inject packets into the PHY/MAC interface. The
two signals from the EM250 are the frame signal (PTI_EN) and the data signal (PTI_DATA). The PTI is supported
by Ember Desktop.
XAP2b Microprocessor
The EM250 integrates the XAP2b microprocessor developed by Cambridge Consultants Ltd., making it a true
system-on-a-chip solution. The XAP2b is a 16-bit Harvard architecture processor with separate program and
data address spaces. The word width is 16 bits for both the program and data sides. Data-side addresses are
always specified in bytes, though they can be accessed as either bytes or words, while program-side addresses
are always specified and accessed as words. The data-side address bus is effectively 15 bits wide, allowing for
an address space of 32kB; the program-side address bus is 16 bits wide, addressing 64k words.
The standard XAP2 microprocessor and accompanying software tools have been enhanced to create the XAP2b
microprocessor used in the EM250. The XAP2b adds data-side byte addressing support to the XAP2 by utilizing
the 15 th bit of the data-side address bus to indicate byte or word accesses. This allows for more productive
usage of RAM, optimized code, and a more familiar architecture for Silicon Labs customers when compared to
the standard XAP2.
The XAP2b clock speed is 12MHz. When used with the EmberZNet PRO stack, code is loaded into Flash memory
over the air or by a serial link using a built-in bootloader in a reserved area of the Flash. Alternatively, code
may be loaded via the SIF interface with the assistance of RAM-based utility routines also loaded via SIF.
The XAP2b in the EM250 has also been enhanced to support two separate protection levels. The EmberZNet
stack runs in System Mode, which allows full, unrestricted access to all areas of the chip, while application
code runs in Application Mode. When running in Application Mode, writing to certain areas of memory and
registers is restricted to prevent common software bugs from interfering with the operation of the EmberZNet
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120-0082-000V Rev 1.1
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相关代理商/技术参数
EM250-COMP-XIDE 制造商:Silicon Laboratories Inc 功能描述:COMPILER XIDE FOR EM250 1SEAT
EM250-DEV 功能描述:KIT DEV FOR EM250 RoHS:否 类别:RF/IF 和 RFID >> RF 评估和开发套件，板 系列:InSight 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
EM250-EK-R 功能描述:KIT EVAL EM250 RF TEST RoHS:是 类别:RF/IF 和 RFID >> 过时/停产零件编号 系列:InSight 标准包装:1 系列:- 类型:用于 200/300 系列的欧盟开发套件 适用于相关产品:Zensys RF 模块 所含物品:开发板，模块，编程器，软件，线缆，电源 其它名称:703-1019Q3225667
EM250-JMP-R 功能描述:KIT JUMP START FOR EM250 RoHS:否 类别:RF/IF 和 RFID >> RF 评估和开发套件，板 系列:JumpStart 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
EM250-RCM-R 功能描述:EM250 RCM BOARD RoHS:是 类别:RF/IF 和 RFID >> RF 评估和开发套件，板 系列:- 标准包装:1 系列:- 类型:GPS 接收器 频率:1575MHz 适用于相关产品:- 已供物品:模块 其它名称:SER3796
EM250-RTR 功能描述:IC ZIGBEE SYSTEM-ON-CHIP 48-QFN RoHS:是 类别:RF/IF 和 RFID >> RF 收发器 系列:EM250 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:30 系列:- 频率:4.9GHz ~ 5.9GHz 数据传输率 - 最大:54Mbps 调制或协议:* 应用:* 功率 - 输出:-3dBm 灵敏度:- 电源电压:2.7 V ~ 3.6 V 电流 - 接收:* 电流 - 传输:* 数据接口:PCB，表面贴装 存储容量:- 天线连接器:PCB，表面贴装 工作温度:-25°C ~ 85°C 封装/外壳:68-TQFN 裸露焊盘 包装:管件
EM250-STACK-R 制造商:Silicon Laboratories Inc 功能描述:EM250 BOARD STACK (RCM + BREAKOUT) - Boxed Product (Development Kits) 制造商:Silicon Laboratories Inc 功能描述:BOARD STACK EM250 RCM & BREAKOUT
EM25-12V-DC 制造商:ECLIPSE MAGNETICS 功能描述:HOLDING ELECTRO MAGNET