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Author Topic: anyone else got the uno+eth_sd from ebay us seller? (Problem fixed!)  (Read 1591 times)
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ok, after all the reading, I think it is clearer now why the issue is with the software reset only.

I just realize now that the 8U2 (16U2 on R3) DTR pin connects in series with the 100nF capacitor on the UNO, and the other end connects the 100nF capacitor on the shield and the reset, and the other end of the shield capacitor is to ground. I think that is how it is trying to delay the reset on the shield. But either the DTR does not stay down long enough or it is unable to discharge the shield capacitor completely, and pressing the reset button helps reset the shield.

Now since the circuit for Uno r2 and r3 are virtually identical with the only difference being the ATmega16U2 vs 8U2, I wonder if that 16U2 is able to do the reset better. Otherwise, I don't know what they mean by R3 having a "stronger reset circuit".

PaulS, you said you don't see this problem. Are you using R3 UNO?

thanks
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... (snip)... Apparently the arduino has to be powered up a fraction of a second before the wiznet shield is powered up. ... (snip)... The issue can be duplicated with an arduino with a non PoE shield installed. Install a simple web server code on the combo and verify it works using a browser. Then unplug/replug the USB connector to the pc to power cycle the arduino/shield. Once the arduino boots up, try to connect to the arduino with the browser. The attempt will fail.

I did that test. My shield's server comes up fine. ??
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Exactly SurferTim.
that is not the same problem as what I described in this thread. it is actually the reverse, that old thread issue is for hard reset and not soft reset.

I power cycled my UNO and eth shield over 100 times with no problem running the webserver program.
My issue is in a soft reset (unable to upload a sketch), not with a hard reset, so I don't think that fix from that old post will fix the soft reset issue.

zoomkat, I take it you have hardware that encountered this issue? what is the version of the board and shield? and which issue did you encounter, the hard reset issue or the soft reset issue?

thanks.
« Last Edit: March 07, 2012, 11:24:38 am by doughboy » Logged

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I did that test. My shield's server comes up fine. ??

I retried the test (both 1.0 and 0022 code) and my old shield also works fine. Maybe it was a momentary problem connecting with the router at the time I was testing. At the time I was also testing powering the arduino with a 5v regulator chip via the 5v pin (not connected/powered via USB) and had to use the reset button to set the ethernet board to connect via a browser. I'll have to do the test again some time using the external power. It appears that the PoE ethernet shields are constructed differently such that the below seller stated actions are required (or do the manual reset) to upload sketches. I've only seen this disclamer with the PoE shields. It might be worthwhile to compare the schematics of the old shields and the PoE shields for differences.   

**(Buyer has to upload sketches to the Arduino mainboard without attaching this ethernet shield on it.  Otherwise sketches can not be uploaded.)

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when you say POE shield, do you mean shield with POE installed?

That statement by the seller is exactly that, it only means the issue is in uploading sketch. No runtime issues like the one described in the old thread.

FWIW, I power cycled using external power (not using USB) and it works every single time. So this is not the same issue as the old thread, as I don't remember reading any mention of problem uploading (or I may have missed it).
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when you say POE shield, do you mean shield with POE installed?

I mean the shield you apparently bought with the upload issue notification.

Quote
FWIW, I power cycled using external power (not using USB) and it works every single time. So this is not the same issue as the old thread, as I don't remember reading any mention of problem uploading (or I may have missed it).

Below is the old issue statement. This issue would be unacceptable for a PoE board, as it needs to have unattended recovery from a power cycle. I just speculate that the PoE boards may have been modified in some way (possibly like the mod to the old boards) to automatically recover unattened from a power cycle. The mod may also have the consequence of requiring a manual reset during program uploading. Bottom line: old boards don't have issues with traditional uploads, new PoE boards do have issues with traditional uploads.

Problem: Arduino 2009 with wiznet w5100 ethernet shield does not start network operations after power-up.
It works well if the reset button is pressed.
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The seller also lists that ethernet shield separately.  In this listing, besides noting the sketch uploading issue, he says that the board is NOT compatible with the Uno.

http://www.ebay.com/itm/W5100-Ethernet-Shield-for-Arduino-Laterest-Version-micro-SD-Card-PoE-Ready-00930-/180840609188?pt=LH_DefaultDomain_0&hash=item2a1af0b5a4

I was just about to order this board but found this thread.  It sounds like you have a partial workaround for the sketch uploading (a manual reset is easier than plugging/unpluggin).

I take it you've had no problem with uno compatibility?

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don't buy it.

I only found out later when my program size got bigger that the darned chip they use has bad memory above 0x7000 address. They probably got the chips from atmel dumpster. I suppose that is one reason they can sell cheaper. And the seller is now giving me the run around and don't want to send me a replacement.

FWIW, this seller's ethernet card is the only one that mentions you have to disconnect it before you upload. So I urge you get it somewhere else.

Anyone knows if it is possible to change an ebay review to 1 star?
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ok, if anyone else got the ethernet shield from the seller from NJ that does not allow uploading without pressing the reset button (or not upload at all with mega), the solution is to remove R1 and C3.

See my post here
http://arduino.cc/forum/index.php/topic,103802.0.html

I just removed R1 and C3 and now I can upload sketch without removing the ethernet shield or pressing reset right before the upload.

you can follow this video on how to remove smt resistor. just alternate the soldering iron tip between the two ends of R1 (and C3) until it comes off.
http://youtu.be/6XyrNjNXSo8

The manufacturer simply followed the published schematic as-is.  There is a disclaimer to the schematic saying it is subject to change without notice. ;^)
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My e-bay shield came without a MAC address. Am I supposed to make up an address in a sketch? Thanks.
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I just removed R1 and C3 and now I can upload sketch without removing the ethernet shield or pressing reset right before the upload.

Have you verified that the shield sill recovers from an interruption to the PoE power?
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