Forums

AT90USB128 to 802.11 wifi adapter

Started by Unknown December 1, 2006
Anyone have any comments on the feasability of connecting a Atmel
AT90USB128 (which has usb host mode interface) to a 802.11g USB adapter
based on something like the Zydas ZD1211?

Seems like it could be a cheap and flexible solution-- but quite a bit
of work, and would require a USB analyzer.  The ZD1211 is supported by
linux, so that would be a good reference, and Atmel provides a simple
host mode example for the AT90USB (for connecting to a keyboard or
mouse).

Too bad USB analyzers are still so expensive.  I even did a little
searching to see if I could find one for rent, but couldn't find any
references.

thanks.

<jakeb221@gmail.com> schrieb
> Anyone have any comments on the feasability of connecting a Atmel > AT90USB128 (which has usb host mode interface) to a 802.11g USB adapter > based on something like the Zydas ZD1211? >
This depends on your application. For the typical networking stuf&#2013266100;f you will need a TCP/IP stack too. I doubt that the performance of the ATMEGA is sufficient to support both, the byte-by-byte handling of the USB WLAN adapter and the TCP/IP communication. However I could imagine applications which use the 802.11 WLAN connection on a packet level i.e. without TCP/IP and in this case this sounds like an interesting idea. /Roland
"Roland Zitzke" <KONULRABFBQR@spammotel.com> skrev i meddelandet 
news:457521d2$1_1@news.ecore.net...
> > <jakeb221@gmail.com> schrieb >> Anyone have any comments on the feasability of connecting a Atmel >> AT90USB128 (which has usb host mode interface) to a 802.11g USB adapter >> based on something like the Zydas ZD1211? >> > This depends on your application. For the typical networking stuf&#2013266100;f you > will need a TCP/IP stack too. I doubt that the performance of the ATMEGA > is sufficient to support both, the byte-by-byte handling of the USB WLAN > adapter and the TCP/IP communication. > However I could imagine applications which use the 802.11 WLAN connection > on a packet level i.e. without TCP/IP and in this case this sounds like an > interesting idea. > > /Roland >
The nice thing about TCP/IP is that if you lose a packet, the protocol will ensure it will be resent. Talked to a customer the other day, and they need to send 16 bits of data every three seconds over TCP/IP/WLAN , and I do not see why this would be a problem for the AT90USB1287. -- Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB
Ulf Samuelsson wrote:
>
... snip ...
> > The nice thing about TCP/IP is that if you lose a packet, > the protocol will ensure it will be resent. > Talked to a customer the other day, and they need to send 16 bits > of data every three seconds over TCP/IP/WLAN , and I do not see > why this would be a problem for the AT90USB1287.
Sounds like overkill to me. Just include a timestamp with the data and use IP. The receiver can then detect missed packets and possibly interpolate. -- Chuck F (cbfalconer at maineline dot net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net>
"Ulf Samuelsson" <ulf@a-t-m-e-l.com> schrieb
> > The nice thing about TCP/IP is that if you lose a packet, > the protocol will ensure it will be resent. > Talked to a customer the other day, and they need to send 16 bits of data > every three seconds over TCP/IP/WLAN , and I do not see why this > would be a problem for the AT90USB1287. >
In this specialized case it would most likely work. The only question is wheter there's a way to get by with the internal memory of this controller. There are TCP/IP stacks around for the AVR like the Ethernut but they do require external RAM. Very often the rational behind using TCP/IP and not some other low level protocol is that the embedded hardware needs to talk to a UNIX or Windows host and these machines handle IP stuff easily. In such case it might even be possible to get by with a UDP communication and manually implement a resend feature. This requires of course that there is no risk of loosing the packet ordering. /Roland
Roland Zitzke wrote:
> "Ulf Samuelsson" <ulf@a-t-m-e-l.com> schrieb >> >> The nice thing about TCP/IP is that if you lose a packet, >> the protocol will ensure it will be resent. >> Talked to a customer the other day, and they need to send 16 bits of >> data every three seconds over TCP/IP/WLAN , and I do not see why this >> would be a problem for the AT90USB1287. >> > > In this specialized case it would most likely work. The only question > is wheter there's a way to get by with the internal memory of this > controller. There are TCP/IP stacks around for the AVR like the > Ethernut but they do require external RAM.
This chip has 8 kB SRAM which helps a little. As long as you only use 1-2 transmit buffers you can live with very low amount of memory. This will have terrible performance when accessing over WAN, but on a LAN it is OK, for these t&#2013266173;pes of applications.
> Very often the rational behind using TCP/IP and not some other low > level protocol is that the embedded hardware needs to talk to a UNIX > or Windows host and these machines handle IP stuff easily. > In such case it might even be possible to get by with a UDP > communication and manually implement a resend feature. > This requires of course that there is no risk of loosing the packet > ordering. > /Roland
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB