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Topic: Ethernet sheild(W5100) not working with Uno (Read 12280 times) previous topic - next topic

Veeru

http://www.countrymilewifi.com/how-to-share-computers-wifi-with-ethernet-devices.aspx

i shared it as described in the above link.

btw i noticed one thing. After reset only the FULLD light blinks. but if i leave the board as it is after some time all the lights are on.

psyazax

I believe both relate to a widespread issue impacting cheap chinese clones of the arduino ethernet modules which incorrectly include a 510 Ohm resistor network (labelled 511) on the network cable connection instead of the specified 49.9 Ohm resistor network.

In a few days I hope to prove this when some replacement resistor networks arrive and i replace mine.
I replace mine with 680=68ohm and start to working. its not 49.9 but i think will do the job.

connectable

Hi keithsw1111, i wonder if your replacement of the resistor network with 49R9 worked? All the schematics I've seen have 49R9 fitted. I have similar problems to yours running an UNO and a chinese clone wiznet board.
Joe.
Assuming there is not a bug in the code you are using:

There are 3 common problems with cheap chinese clones of these shields ...

1. No ip address and no matter how often you reset it it never sticks ... this seems to be a SPI connection issue. Ensure your shield is correctly seated.
2. No ip address or a random one on start. If you press the reset button and it restarts it works.
3. IP address sticks and when directly connected to a PC it works but through a switch you cannot communicate.

I believe both relate to a widespread issue impacting cheap chinese clones of the arduino ethernet modules which incorrectly include a 510 Ohm resistor network (labelled 511) on the network cable connection instead of the specified 49.9 Ohm resistor network.

In a few days I hope to prove this when some replacement resistor networks arrive and i replace mine.

connectable

sorry psyazax,
I didn't notice your post (noobie) - glad to hear you got it working. BTW HanRun (who make the ethernet Tx/Socket, show 75 ohms - so 68R looks like a good compromise. I haven't got a network resistor, but do have separate SMD resistor, so will try this amanha. Regards, Joe.
I replace mine with 680=68ohm and start to working. its not 49.9 but i think will do the job.


k1ggi

The Ethernet twisted-pairs are transmission lines that really need 100 ohm differential termination, 2 each 49.9, per the reference schematic, or 2 each 51 would be ok too. But without proper termination, it is easy to be on (or beyond) the fringe of workability. On the fringe, one cable might appear to make things work, where another doesnt.
As noted, the problematic boards are coming with 2 each 510 ohm, per measurement and per their 511 marking, 51*10^1.
An easy and satisfactory solution is to come up with a couple of 100 to 120 ohm resistors to tack across the HanRun connector pins. One goes between pins 1 and 2, the other between pins 3 and 6. Leave the bogus resistor pack in place, it works to supply the necessary bias. No need to fiddle with sourcing and changing the tiny pack.
I just received additional boards from a US ebay vendor whose picture showed 510 marking (51 ohm), but 511 on the batch received. Added the discrete resistors (100 ohm on hand) and the Ethernet waveforms are close to picture perfect.
The built-in 75 ohm resistors in the HanRun mag jack are not differential signal terminating resistors, they are involved with common-mode behavior, tied to the center taps of the transformers.
Ed

ahoicaptain

Hello guys,

I'm having a similar issue. I have the same cheap Chinese ethernet shield using the W5100 and when I first got it I used a long ethernet cable (around 10 meters) to connect it and everything was perfect. Today, (a month later - I used it only twice before) I used a different cable (15 meters exactly) to connect it in my modem/router and run a code I found for getting the local IP. For a few seconds everything was normal (all the LEDs where on) and suddenly it stopped working. The only LED that works is the red one (PWR). I tried everything, I changed arduinos, I used a 9V battery in case there was something wrong with my USB port, I checked the ethernet cable in case it wasn't working (It works), but nothing changed until I used a small cable I had. When I plugged it in, it was back to normal. I tried the method above mentioned by Ed and when I pressed the reset button it worked for 3-4 secs - until the yellow led on the ethernet port (made by HanRun) got burned. I used a second ethernet shield I had with the long ethernet cable and it was ok. Is there anything I could try to make it work with the long cable or should I give up? (By the way, the on board resistor is 511)

Thanks,
Dimitris

zoomkat

Quote
For a few seconds everything was normal (all the LEDs where on) and suddenly it stopped working.
I'd suspect a poor/intermittent connection in the RJ45 connectors.
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jpescola

I have the same problem. I found that it works normally if the cable is plugged into an older router Encore ENHWI . I believe that is a difference between the two routers . Someone tried to cross cable ?

ahoicaptain

I'd suspect a poor/intermittent connection in the RJ45 connectors.

Unfortunately no. I checked it thoroughly.

k1ggi

Dimitris,
Can you post a photo of how you installed the terminating resistors, just to be sue they are on the right pins?
15 meters of cat5e should work fine.
Ed

ahoicaptain

Dimitris,
Can you post a photo of how you installed the terminating resistors, just to be sue they are on the right pins?
15 meters of cat5e should work fine.
Ed
Hi Ed,

Sorry for the delay!

This is the picture:

Dimitris

ffur

There is a slight misunderstanding here.
It's not the shield pins 1 and 2, 3 and 6, but the pins on the 'Hanrun' Ethetnet socket.

/ffur

rostit

Hello.  I signed up just to reply to this thread.  I purchased a few of these chinese W5100 boards and have been going nuts trying to get them running.  The resistor network is definitely the issue.

There are a few ways to re-work it without the 49ohm network.

I used 47ohm radial resistors and tried 2 different methods.  Both were successful.

Hopefully my pictures and notes help.

First method:

1. Remove the resistor network labeled 511 behind the RJ45 socket. I used a hotair station. Careful hand iron would work with some chipquick solder probably.
2. On the bottom solder shortened leads to pins 1,2,3,6. (Watch pin3, space the lead carefully)
3. combine the loose ends of 1,2 and then 3,4. 
4. Run hookup wire from the junction of 1,2 to the cap behind the rj45 socket, on the end closest to the socket.
5. Run hookup wire from junction of 3,4 to the cap to the right of the 102 resistor network, also to the side closest to the RJ45 socket.

Second method:
1. Remove the resistor network labeled 511 behind the RJ45 socket. I used a hotair station. Careful hand iron would work with some chipquick solder probably.
2. Fold 4x 47 ohm resistors so they are radially configured. Snip the leads about 3mm from the bottom of the resistor. Then tin the ends with solder
3. Installing the resistors in an alternating pattern(for space) you can tack them to the surface mount pads. I was able to tack one side at a time and then go back to add more solder, being careful not to bridge any pads.  **I found removing the RJ45 socket made this much easier**
4. The side of the pads away from the RJ45 socket are common to the capacitors, so you can double up and cross over the pads for each pair.  Meaning pad1 and 2 can share the opposite side and 3,4 respectively.

The first method seems to be the easiest using 1/4w resistors.  I have some 47ohm surface mount resistors at work that I may try, but with what I had at home, this worked quite well.

Here are some images of the re-work.  I tested using the Webserver sample code and it worked immediately.

Link to Imgur gallery (images are larger than 1mb)  http://imgur.com/a/JrPFD


Hope this helps!




k1ggi

Hello Dimitris,
Here is a photo of the terminations applied to the HanRun connector.

ahoicaptain

There is a slight misunderstanding here.
It's not the shield pins 1 and 2, 3 and 6, but the pins on the 'Hanrun' Ethetnet socket.

/ffur
Hello Dimitris,
Here is a photo of the terminations applied to the HanRun connector.

Damn! I feel like an idiot now, hahahah! Thanks guys I will try that!

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