Reply by Ulf Samuelsson December 8, 20062006-12-08
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&#4294967295;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
Reply by Roland Zitzke December 5, 20062006-12-05
"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
Reply by CBFalconer December 5, 20062006-12-05
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>
Reply by Ulf Samuelsson December 5, 20062006-12-05
"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&#4294967295;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
Reply by Roland Zitzke December 5, 20062006-12-05
<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&#4294967295;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
Reply by December 1, 20062006-12-01
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.