T76C502 - SeattleWireless

Atmel has decided to join the selected club of company selling 802.11b chipsets. Their design is based on an ARM7 processor, and offer a Pcmcia and a USB version. The USB version is by far the most popular, because it was first to market. Various 802.11b radios can be used with this chipset (such as the PrismII radio). Very little public information is available about those products, but as they are 802.11 compliant we can expect the usual set of features.

Of course, with any USB cards the main issue is performance. The streaming abstraction of USB doesn't work well with register/memory based chipset designs and slow down operations. Also, USB add a noticeable latency. I currently don't have any data on how well those cards performs in the respect.

Linksys and D-Link are selling various USB products based on this chipset, such as Gemtek WL-280, D-Link DWL-120, Linksys WUSB11... It seems that the SMC 2632W is a Pcmcia card also based on the Atmel chipset.

The newly released 3Com OfficeConnect Wireless LAN cards (3CRSHPW196/696 - with or without the XJack antenna) and new 3Com Wireless LAN XJack (3CRWE62092B) are also Atmel Pcmcia cards.

30.2 The driver

Atmel decided to release themselves a Linux driver. This driver is in fact a set of driver for the different combination of controllers and radios, and was initially based on a binary library. However, Atmel changed their mind and eventually released the driver as full source GPL. The USB versions work with both uhci and ohci USB drivers. The driver support WEP and Ad-Hoc mode.

The package from Atmel include specific configuration tools (command line and X-Window). Just after the driver was GPL'ed, the support for Wireless Extensions was fixed and greatly enhanced by Ron (Wireless Tools can now be used to configure the card). Lately, Atmel has improved and enhanced the USB driver, but also removed support for Intersil radio, so you will need to use older version of the driver for products using Intersil radio. On the other hand, the Pcmcia driver seems to be still based on an older version of the code.

Jason and various people are hosting the driver and collecting information about it on their web page.

31 Atmel USB alternate driver

Driver status : in development

Driver name : USB : at76c503.o

Version : 0.10

Where : http://at76c503a.berlios.de/

http://innominate.org/kurth/at76c503/

Maintainers : Jörg Albert <joerg dot albert at gmx dot de> Oliver Kurth <oku at masqmail dot cx>

Web page : http://at76c503a.berlios.de/

http://innominate.org/kurth/at76c503/ http://www.wireless.org.au/~jhecker/atmeldrv/atmeldrv.html

Mailing lists : http://lists.berlios.de/pipermail/at76c503a-user/ http://iprserv.jura.uni-leipzig.de/mailman/listinfo/atmel-wlan-usb

Documentation : Readme files

Configuration : Wireless Extensions

Statistics : Wireless Extensions

Multi-devices : ?

Interoperability : 802.11-DS and 802.11-b, interoperate with Windows

Other features : Intersil radio support

Non implemented : -

Bugs : -

License : GPL

Vendor web page : http://www.atmel.com/atmel/products/prod32a.htm http://www.gemtek.com.tw

http://www.dlink.com/products/wireless/index.asp http://www.linksys.com/products/

31.1 The device

This is the same device as the previous entry (section 28).

31.2 The driver

Oliver and a group of people were not happy about the official Atmel driver and its development (section 30), and therefore he started to write an alternate driver from scratch, based on the information available in the official driver, and soon those other people started to help him.

The driver support only USB devices, and it support both Intersil and RFMD radios. At this time, the new driver is still in development, and therefore still has some limitations, but it already support both infrastructure and ad-hoc mode, and has some Wireless Extension support.

As Olivier was no longer active, Jörg took over the driver and is now fixing many bugs, making it more robust and adding a few missing features.

32 Atmel Pcmcia alternate driver

Driver status : in development

Driver name : Pcmcia : atmel_cs.o

Version : 0.7

Where : Kernel 2.5.71

Maintainers : Simon Kelley <simon@thekelleys.org.uk>

Mailing lists : http://sourceforge.net/mail/?group_id=59001 http://iprserv.jura.uni-leipzig.de/mailman/listinfo/atmel-wlan-usb

Documentation : Readme files

Configuration : Wireless Extensions

Statistics : Wireless Extensions

Multi-devices : ?

Interoperability : 802.11-DS and 802.11-b, interoperate with Windows

Other features : Wireless Scanning

Non implemented : -

Bugs : -

License : GPL

Vendor web page : http://www.atmel.com/atmel/products/prod32a.htm http://www.3Com.com/ http://www.smc.com/

32.1 The device

This is the same device as the previous entry (section 30).

32.2 The driver

Simon also was not happy with the original Atmel driver. He decided to rewrite the Pcmcia/PCI driver based on the original code, with the main target being integration in kernel 2.5.X (which is now done). Simon did an extensive amount of work on the driver, for example his driver has very complete Wireless Extension support including Wireless Scanning. However, this driver is not compliant with kernel 2.4.X and earlier.

This driver has only been tested with Pcmcia cards, if you want PCI card support you should contact Simon. Some of those cards don't have firmwares and therefore need to use the new firmware uploading facility of Linux, which is currently being finalised.