Zigbee IEEE 802.15.4RF 部分是定频还是跳频呢？
CC2530F32, CC2530F64,CC2530F128, CC2530F2561FEATURES – IEEE 802.15.4 MAC Timer, General-Purpose
Timers (One 16-Bit, Two 8-Bit)
2345• RF/Layout
– IR Generation Circuitry
– 2.4-GHz IEEE 802.15.4 Compliant RF
APPLICATIONS
Microcontroller Core With Code Prefetch • 2.4-GHz IEEE 802.15.4 Systems
– 32-, 64-, 128-, or 256-KB • RF4CE Remote Control Systems (64-KB Flash
and Higher) In-System-Programmable Flash
• ZigBee Systems (256-KB Flash)
DESCRIPTION
The CC2530 is a true system-on-chip (SoC) solution for IEEE 802.15.4, Zigbee and RF4CE applications. It enables robust network nodes to be built with very low total bill-of-material costs. The CC2530 combines the excellent performance of a leading RF transceiver with an industry-standard enhanced 8051 MCU, in-system programmable flash memory, 8-KB RAM, and many other powerful features. The CC2530 comes in four different flash versions:
CC2530F32/64/128/256, with 32/64/128/256 KB of flash memory, respectively. The CC2530 has various operating modes, making it highly suited for systems where ultralow power consumption is required. Short transition times between operating modes further ensure low energy consumption. Combined with the industry-leading and golden-unit-status ZigBee protocol stack ( Z-Stack™) from Texas Instruments, the CC2530F256 provides a robust and complete ZigBee solution. Combined with the golden-unit-status RemoTI stack from Texas Instruments, the CC2530F64 and higher provide a robust and complete ZigBee RF4CE remote-control solution
Physical and MAC Specifications
Frequency2.4 GHz915 MHz868 MHz
Data Rate250 kb/s40 kb/s20 kb/s
Channel Count16101
ModulationO-QPSKBPSKBPSK
ZigBee is built on top of the physical layer and medium access control (MAC layer) defined in the IEEE standard 802.15.4 (2003 version) for low-rate WPAN's. The Zigbee specification then adds to the standard four main components: network layer, application layer, ZigBee device objects (ZDO's) and user-defined application objects which allows for customization and flexibility within the standard.
In addition to integrating two high-level network layers to the underlying structure, the most significant addition is the introduction of Zigbee Device Objects (ZDO's). ZDO’s are responsible for multiple tasks, which include defining device roles, management of requests to join a network, device discovery and security.
By nature, ZigBee is a “mesh network” architecture. In addition to the mesh topology the network layer supports two other types of topologies: star and tree. Every network must have one Zigbee Coordinator device, tasked with its creation, the control of its parameters and basic maintenance. Within star networks, the ZC is the central node. Both tree and mesh networks allow the use of ZigBee Routers to extend communication at the network layer.
Zigbee can be configured as a beacon or a non-beacon enabled network.In a non-beacon network, CSMA/CA is used, and the Zigbee Routers are continuously active.This allows other Zigbee devices to only transmit when an external stimulus is received from a Zigbee Router.The other type is a beacon enabled network.In this configuration the Zigbee routers send periodic beacons to confirm their existence to the rest of the nodes.In between beacons nodes can sleep, which allows for extended battery life.As a result of this the network requires precise timing for transmitting and receiving.This requires more complex devices which can drive up costs.
呵呵，据我所知，是DSSS类型 本帖最后由 曾大侠 于 2015-3-31 19:52 编辑
Helen.ma 发表于 2015-3-31 07:58
呵呵，据我所知，是DSSS类型
我在Zigbee IEEE 802.15.4里面看到Zigbee有DSSS、BPSK、PSSS、CSS、BMP、MPSK好几种调制类型，详细如下诉述：
The PHYs defined in this standard are:
— O-QPSK PHY: direct sequence spread spectrum (DSSS) PHY employing offset quadrature phaseshift keying (O-QPSK) modulation, operating in the 780 MHz bands, 868 MHz, 915 MHz, and 2450 MHz, as defined in Clause 10.
— BPSK PHY: DSSS PHY employing binary phase-shift keying (BPSK) modulation, operating in the 868 MHz, 915 MHz, and 950 MHz bands, as defined in Clause 11.
— ASK PHY: parallel sequence spread spectrum (PSSS) PHY employing amplitude shift keying (ASK) and BPSK modulation, operating in the 868 MHz and 915 MHz bands, as defined in Clause 12.
— CSS PHY: chirp spread spectrum (CSS)employing differential quadrature phase-shift keying (DQPSK) modulation, operating in the 2450 MHz band, as defined in Clause 13.
— UWB PHY: combined burst position modulation (BPM) and BPSK modulation, operating in the sub-gigahertz and 3–10 GHz bands, as defined in Clause 14.
— MPSK PHY: M-ary phase-shift keying (MPSK) modulation, operating in the 780 MHz band, as defined in Annex G.
— GFSK PHY: Gaussian frequency-shift keying (GFSK), operating in the 950 MHz band, as defined in Clause 15.
8.1.1 Operating frequency range A compliant device shall operate in one or several frequency bands using the modulation and spreading formats summarized in Table 66.
Devices shall start in the PHY mode in which they are instructed to start. If the device is capable of operating in the 868 MHz or 915 MHz bands using one of the optional PHYs described in Clause 10 and Clause 12, it shall be able to switch dynamically between the optional PHY and the mandatory BPSK PHY
in that band when instructed to do so.
If the 950 MHz band is supported, then at least one of the 950 MHz band PHYs shall be implemented
我只做过2.4G频段的，O-QPSK的，原来不同频段还有这么多调制方式，长知识了，多谢曾大侠 Helen.ma 发表于 2015-3-31 21:57
我只做过2.4G频段的，O-QPSK的，原来不同频段还有这么多调制方式，长知识了，多谢曾大侠
多翻翻资料就有了，不客气
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