ISL36356A-APDK データシートの表示（PDF） - Intersil
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ISL36356A-APDK Datasheet PDF : 7 Pages
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ISL36356A-APDK
Functional Overview
The WLAN Access Point is designed to operate in the
2.4GHz ISM frequency band, channels 1 to 11, as specified
by the FCC in the USA. The AP will also operate on
channels 12 through 14, where permitted by local regulatory
authorities. Radio equipment must be certified in a country
prior to use. Refer to Table 4 for a list of countries and
agencies that have approved the ISL36356A-APDK for
operation.
The Intersil PRISM II Chip Set allows for high level
integration; providing reduced size, increased throughput,
improved radio performance and faster time to market. The
WLAN Access Point implements Direct Sequence Spread
Spectrum DSSS technology that provides superior noise and
signal jamming immunity; including less severe impact from
unintentional radiators such as microwave ovens. By using
an Access Point, the wireless LAN can be set up to allow an
even greater number of users to interconnect, and to
increase the coverage area. The wireless LAN can be easily
connected into an existing wired LAN, allowing for easy
expansion of the service.
The ISL3856 Media Access Controller
(MAC) Protocol Handler
The ISL3856 ARM940 based MAC Processor and the MAC
Virtual Coprocessor (MVC) firmware are responsible for
running the IEEE802.11 protocol in the WLAN AP. The MVC
acts as a software emulated coprocessor to the ARM940
and runs completely separated from the operating system. It
provides an abstraction layer of the underlying hardware to
the operating system via a well-defined interface.
The MVC supports the following 802.11 functions:
• CSMA/CA (Carrier Sense Multiple Access with Collision
Avoidance) with Random Backoff
• WEP Security
• Short/Long Preamble with multirate
• RTS/CTS Handshake (Ready To Send/Clear To Send)
• MAC Level Acknowledgments (Media Access Control)
• Re-Transmission of Unacknowledged Frames
• Duplicate Detection and Rejection
• Broadcast and Multicast Frames
• Fragmentation and Re-Assembly
• Supports clients Power save mode
• Timestamp Synchronization
• DCF (Distributed Coordination Function)
The Linux Operating System
The ARM940 based MAC processor hosts a complete Open
Source Linux operating system, offering a flexible and
extensible platform for feature development. Due to the large
availability of different Linux based applications in the Open
Source community, it is easy to add new features to the AP,
reducing time to market.
A special embedded version of the Linux operating system,
uClinux, is running on the ISL3856. It is tailored to run on the
ARM940 processor and optimized for size. The uClinux
Application Programmers Interface (API) is the same as the
standard Linux API. The ISL36356A platform offers the
following basic functions:
• DHCP client/server
• Configuration via Web Interface and SNMP
• Simple and Failsafe Firmware Upgrade via Web Interface
• Wi-Fi Protected Access (WPA)
• 802.1x Security
• Wireless Distribution System
• Routing, NAPT and firewall support
• PPPoE
• VPN Passthrough (PPTP)
• 802.1d Spanning Tree Protocol (STP)
Adding features to the development platform can be done by
taking applications that are available in the Open Source
community and port them to the platform. Porting
documentation is available to assist in this task. Applications
can also be made from scratch, so they can be kept closed
source.
The table below lists the resources that are available for
adding new applications to the basic design. In normal
operation, approximately 50% of the processor cycles of the
ARM940 are consumed by the MVC. The remaining capacity
is available for Linux and the applications. Because all
applications are stored in Flash in a compressed format, the
available Flash is calculated for both compressed and
uncompressed files.
TABLE 2. AVAILABLE RESOURCES
MEMORY
AVAILABLE
CONFIGURATION
RAM
AVAILABLE FLASH
(COMPRESSED /
UNCOMPRESSED)
2Mbyte Flash
8Mbyte RAM
~1.2Mbyte
~16kbyte / 32kbyte
4Mbyte Flash
16Mbyte RAM
~9.2Mbyte
~2.0Mbyte / 4.0Mbyte
For starting development on the Linux based platform, a
complete development environment is shipped with the
product, including documentation describing the setup of a
development system.
The complete hardware and software of the system are
pretested which ensures a stable development platform.
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