"Casey" <cclremovethispart@cox.net> skrev i meddelandet news:kQ5Zb.4216$23.677@lakeread04...> Albert Lee Mitchell said... > > On Wed, 18 Feb 2004 22:39:06 -0800, Devyn wrote: > > > > > Greetings All! > > > > > > I'm a final year EE engineering student working with > > > microcontrollers. As part of my course i'm supposed to design and > > > implement an embedded sys. I thought of controlling some application > > > through the internet. > > Can't help but to notice the good responses he's getting by > being upfront about this being school-related as opposed to the > the ones posting poorly-disguised homework questions. >...> How about an on-line refrigerator with an optical beer-counter > inside? With a web-enabled cellphone you could easily decide > the correct amount to purchase while standing in the grocery > store. > >This is because he is not asking someone to design it for him. He is just asking for a good application. Key to succeeding is here to limit the size of the application. Most people I talk to that want to do Telematics are looking for 2 MB of Flash. I'd hate to write 2 MB of code for a students project. -- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This is a personal view which may or may not be share by my Employer Atmel Nordic AB
Embedded Internet
Started by ●February 19, 2004
Reply by ●February 20, 20042004-02-20
Reply by ●February 21, 20042004-02-21
Ulf Samuelsson said...> "Casey" <cclremovethispart@cox.net> skrev i meddelandet > > Albert Lee Mitchell said... > > > On Wed, 18 Feb 2004 22:39:06 -0800, Devyn wrote: > > > > > > > Greetings All! > > > > > > > > I'm a final year EE engineering student working with > > > > microcontrollers. As part of my course i'm supposed to design and > > > > implement an embedded sys. I thought of controlling some application > > > > through the internet. > > > > Can't help but to notice the good responses he's getting by > > being upfront about this being school-related as opposed to the > > the ones posting poorly-disguised homework questions. > > > ... > > How about an on-line refrigerator with an optical beer-counter > > inside? With a web-enabled cellphone you could easily decide > > the correct amount to purchase while standing in the grocery > > store. > > This is because he is not asking someone to design it for him. > He is just asking for a good application.True, which makes it interesting to discuss and play around with.> Key to succeeding is here to limit the size of the application. > Most people I talk to that want to do Telematics are looking for > for 2MB Flash. > I'd hate to write 2 MB of code for a students project.Me too. It would be even worse if all of it had to work. Casey
Reply by ●February 21, 20042004-02-21
You may consider Hitachi processors. Very powerfull devices, and lot of tools. An example at: http://www.stacktools.com/page/cdir.c?dir=ucmodules/ST2011 Cheers, Gerard Zagema
Reply by ●February 21, 20042004-02-21
Marko said...> You may consider Hitachi processors. Very powerfull devices, and lot of > tools. > > An example at: > > http://www.stacktools.com/page/cdir.c?dir=ucmodules/ST2011Sorry, but that's one of the most uninformative web sites I've seen in some time. Might want to finish it some of it first before giving the URL out. Casey
Reply by ●February 21, 20042004-02-21
Casey wrote:> Marko said... > >>You may consider Hitachi processors. Very powerfull devices, and lot of >>tools. >> >>An example at: >> >>http://www.stacktools.com/page/cdir.c?dir=ucmodules/ST2011 > > > Sorry, but that's one of the most uninformative web sites I've > seen in some time. Might want to finish it some of it first > before giving the URL out.Yet another person learns how to hang a Realtek ethernet chip on a cheap processor and port a open-source stack to it...
Reply by ●February 22, 20042004-02-22
On Sat, 21 Feb 2004 19:39:27 +0000, Owlmeat wrote:> Casey wrote: >> Marko said... >> >>>You may consider Hitachi processors. Very powerfull devices, and lot of >>>tools. >>> >>>An example at: >>> >>>http://www.stacktools.com/page/cdir.c?dir=ucmodules/ST2011 >> >> >> Sorry, but that's one of the most uninformative web sites I've >> seen in some time. Might want to finish it some of it first >> before giving the URL out. > > Yet another person learns how to hang a Realtek > ethernet chip on a cheap processor and port > a open-source stack to it...Well, to give him credit, at least he accomplished something. That was an invaluable lesson, if he understood the source code. I'm sure his next version will have significant improvements. My problem with the Realtek parts is that they require most/all of the pins available on an embedded microcontroller and mos/all of the cpu resources. This is why we went with the WC3100 and Cygnal, most of the i/o and cpu is still available for applications. Just serving webpages doesn't do us much good unless the 'server' can do something of value like turn a lamp or toaster on/off at least. -- Regards, Albert ---------------------------------------------------------------------- AM Research, Inc. The Embedded Systems Experts http://www.amresearch.com 916.780.7623 ----------------------------------------------------------------------
Reply by ●February 23, 20042004-02-23
> Yet another person learns how to hang a Realtek > ethernet chip on a cheap processor and port > a open-source stack to it... >Well, StackTos is not an open project but it is our own OS. It is working now for several years in some hostile environments. But I know, it's always easier to criticize then to give some constructive information. To hang an Ethernet controller on a cheap processor that is what this discussion is about, if I'm right, so I don't understand the insinuations....or is it a compliment? In that case......Thanks. Gerard Zagema
Reply by ●February 23, 20042004-02-23
> My problem with the Realtek parts is that they require most/all of the > pins available on an embedded microcontroller and mos/all of the cpu > resources. This is why we went with the WC3100 and Cygnal, most of the > i/o and cpu is still available for applications. Just serving webpages > doesn't do us much good unless the 'server' can do something of value like > turn a lamp or toaster on/off at least. > > -- Regards, AlbertWell, you can memory map the Realtek so it will cost you one additional line (CS). You also can use the READYIO and connect it to the wait pin (another line). It's possible to use the DTC (data transfer controller) to retrieve the data from the RealTek in background. All the other pin's and ports are for the fun of the user so you can switch/control more then you probably ever need for an embedded project like this. The modules like ST2011 are used quite a lot now for ModBUS interfaces and GUI's for PLC's. You don't need any more pins then the RS485. But we have also user who use this device for monitoring temperature and controlling Fan's for potatoes conservation. They use four of the 8 ADC's inputs and two outputs for relais. Regards, Gerard Zagema
Reply by ●February 23, 20042004-02-23
On Mon, 23 Feb 2004 15:46:23 +0100, Gerard Zagema wrote:> >> My problem with the Realtek parts is that they require most/all of the >> pins available on an embedded microcontroller and mos/all of the cpu >> resources. This is why we went with the WC3100 and Cygnal, most of the >> i/o and cpu is still available for applications. Just serving webpages >> doesn't do us much good unless the 'server' can do something of value like >> turn a lamp or toaster on/off at least. >> >> -- Regards, Albert > > Well, you can memory map the Realtek so it will cost you one additional line > (CS). You also can use the READYIO and connect it to the wait pin (another > line). It's possible to use the DTC (data transfer controller) to retrieve > the data from the RealTek in background.Of course you can but not at the cost of a single pin. To interface directly with a Realtek, not just the PHY chip, requires address and data pins which eat all the h/w resources of a microcontroller. If no h/w resources remain why bother? Nobody needs a webserver that's not extensible. For instance how would you interface a LCD and keypad after all the I/O has been eaten in the Realtek interface?> All the other pin's and ports are for the fun of the user so you can > switch/control more then you probably ever need for an embedded project like > this. The modules like ST2011 are used quite a lot now for ModBUS interfaces > and GUI's for PLC's. You don't need any more pins then the RS485.I disagree. Bill Gates once asked, "Why would anyone want more than 640k of RAM?" History proves that users will quickly swallow every feature and ask for more.> But we have also user who use this device for monitoring temperature and > controlling Fan's for potatoes conservation. They use four of the 8 ADC's > inputs and two outputs for relais.That's a great start. Do you have the CPU resources to do a Fuzzy Inference between web requests or to do an interpolation of non-linear data? When your hardware _and_ software are maxed out it severely limits the possiblities. I prefer to design for the future, not the past. -- Regards, Albert ---------------------------------------------------------------------- AM Research, Inc. The Embedded Systems Experts http://www.amresearch.com 916.780.7623 ----------------------------------------------------------------------
Reply by ●February 24, 20042004-02-24
On Mon, 23 Feb 2004 08:11:21 -0800, Albert Lee Mitchell wrote:>> Well, you can memory map the Realtek so it will cost you one additional line >> (CS). You also can use the READYIO and connect it to the wait pin (another >> line). It's possible to use the DTC (data transfer controller) to retrieve >> the data from the RealTek in background. > > Of course you can but not at the cost of a single pin. To interface >directly with a Realtek, not just the PHY chip, requires address and data >pins which eat all the h/w resources of a microcontroller.I think Gerard was referring to designs which already interface to an external memory bus. In those circumstances, the CS line could well be externally decoded, along with all else, in a PAL or whatever. That's the benefit of memory mapping everything - zero overhead. But even using a true microcontroller, the overhead of the RTL8019AS isn't all that great, since you don't actually need most of the address lines, and they can just be pulled. An example is Microchip's POC board for 10-baseT, which uses only five address lines, or 15 I/Os in total - reasonable on a 40-pin chip with 33 I/Os: http://www.microchip.com/download/tools/picmicro/demo/pdemnet/39563b.pdf>If no h/w >resources remain why bother? Nobody needs a webserver that's not >extensible. For instance how would you interface a LCD and keypad after >all the I/O has been eaten in the Realtek interface?They aren't. Many pins on complex chips aren't really essential to basic operation, and good embedded designers learn to cut out the dead wood.>I prefer to design for the future, not the past.You're never required to deliver real working systems today, then? Nice job. -- Max
