Crossover cable

[MSL]

Caretaker: This is how the LED's are on the EtherDongle I have been trying to get to work: The green LED on the PCB comes on; no lights on the MagJack come on.

What I stated in my last post was that I have a second EtherDongle (that also does not work). When the second one is powered up the green light on the MagJack comes on (which tells me that MagJack is working) but the green LED on the PCB does not.

I took the MagJack off the second EtherDongle that the MagJack was working on and put it on the first EtherDongle so I know the MagJack on the EtherDongle I am working on has a MagJack that is functioning.

I also installed the MagJack from the first EtherDongle (that did not light up) onto the second EtherDongle. That MagJack now lights up on the second EtherDongle.

By switching the MagJacks it tells me that the problem most likely is not with the MagJack.

Of course, I know very little about what I am attempting to do. I could be wrong about the MagJacks. That is why I am asking for help from those who know how this works.

Once I get the first one working I will attempt to get the second one to work. By then I will know a lot more about how to trouble shoot the board and hopefully will be able to fix it myself.

Mark

[caretaker]

Hi Mark,  Thanks for making that clear,  with your second one where the Magjack green LED lights but the Green LED on the board doesn't try reprogramming the PIC or the off chance the LED is bad check that. Your first one RJ may have to chime in OR better yet give him a PM with the details and he will be able to give you some precise things to check. When I had problems with mine he had me check a couple things and I was able to pin point and fix the problem. 

[MSL]

I erased the chip, unplugged the power and powered it back up and the green light on the PCB comes on. Why? I thought it only came on if the PIC was programmed.

I re-flashed the PIC. Is it suppose to take 90+ seconds to flash the firmware?

[tbone321]

Nope, that is way to long.  Take a close-up pic of the large processor like you did with the small one and post it.  With this much time, it could also be that the crystal oscillator has failed.

[MSL]

Attached is a photo of the large PIC. I checked the legs. They are all attached (they do not move). I do not see any bridges.

[MSL]

Since I have two EtherDongles and both take a long time to flash maybe it's not the EtherDongles, Maybe it is how I am flashing them.

Before I attempted to flash either of the EtherDongle I opened MPLAB and updated the software. I am running v8.92.

I do not use MPLAB to flash the EtherDongle, only the PICKit 3.

The following are the steps I take to flash the EtherDongle:

*Power the EtherDongle with the 6v transformer (I find that if I do not the flash will fail).
*Plug in the Pickit 3 onto the board (lining up the arrows).
*Double click the Pickit 3 shortcut on my laptop (which takes about 15 seconds to open).

Once the PICKit 3 software opens there is a message in the dialog box that states (from bottom up):

"Found 1 firmware suite: latest is version 01.38.51"
"Loaded device file with 679 devices"
"Found PICkit 3. SN: DEFAULT_PK3" 

The check box under "Program Memory" is checked automatically.
The check box under "EEPROM Data" is checked automatically.

*I click the "Device Family" dropdown (on top) and choose "PIC32".
*Click the "Device" dropdown and choose the last PIC in the list which is "PIC32MX795F512L". It takes about 8 seconds to load PIC information.
*Click on "File" and choose "Import Hex". A folder opens where I have the "EtherDongle_DMX.hex" file. I double click on the file (it takes about 3 seconds to load).
*Click the "On" box under "Target Power". The value changes to "3.38".
*Click on "Write"

At this point it has taken anywhere from 50 to 90 seconds for the "flash" to complete.

Once completed It shows in the dialog box (from bottom up):
"Erasing device"
"Programming device... Program... Boot... done"

I unplug the PICkit 3 from the board. I unplug the 6v power to the board.

When I plug the 6v power back into the EtherDongle there is a green LED on the PCB and no lights on the MagJack.

Am I doing something wrong or missing a step?

[tbone321]

It could be one of your crystal oscillators in not functioning anymore.  This will cause the PIC to run on its internal clock which I believe is much slower which will prevent the ETD from functioning properly.  I would also check to make sure that there isn't an issue with the firmware.  You could download the PixelNet version and loaf that into the ETD and see if anything is different.  You can also check for any output on the oscillators.  You can get the data sheet from mouser to see what the pins are.  While a scope is required to get the actual output of the oscillator, you can use a DVM to see if it is pitting out anything.  You need to check for voltage and how much between the output and ground.  A reading of 0 or the full input voltage here indicates a failed oscillator.  Beyond this, you will need to contact RJ for specific test points to determine exactly what is wrong.  You may also want to start working with the other ETD since it seems to have more life in it than this one has.

[rmp2917]

Check the voltages as shown on this picture. They should be somewhat close to what is listed. This should tell you if there are any issues with the regulators or oscillators.

[MSL]

Thanks for the information Rick.

I went over the voltages. They are as follows:

8 MHz oscillator
CLK (1.8v) reading 1.654v
(3.3v) reading 3.306

50 MHz oscillator
CLK (1.8v) reading 1.639v
(3.3v) reading 3.307v

1117v33
GND
(3.3v) reading 3.311v
(5v) reading 4.96v

7805
(V in)reading 8.3v
(GND)
(5v) reading 4.97v

Around Small PIC
top (3.3v) reading 3.31v
bottom (3.3v) reading 3.31v
TP (1.8 - 2.0v) reading 1.691v

Does the CLK voltage of 1.654v and 1.639v on the oscillators fall within operating parameters?

[rmp2917]

The voltages look OK. The clock and TP1 voltages will not be exact since it is actually a square wave output and not a constant voltage. The readings you are getting look normal and indicate that the regulators, oscillators and the small surface mount chip appear to be working.

[rmp2917]

I know that you said you have two etherdongles. Are all of the pictures here from the same Etherdongle?

Make sure that the 8 MHz and 50 MHz oscillators are not swapped. This will definitely keep the magjack form working. In the one picture here where I can see them, they look correct.

I believe the magjack should light up and work when plugged into a PC even if the PIC is not programmed or not working. So, I don't think your problem has anything to do with the PIC.

I will try to come up with some other things for you to check when I get some time this evening.

Rick

[MSL]

Rick: Yes. I am only working on the one EtherDongle. All the photos are from that one. If I need help with the other one I will start a new topic. Hopefully once I get to the bottom of this one I will have enough knowledge to troubleshoot the other one.

I have checked the placement of the 8 MHz and 50 MHz oscillators. They are in the correct position. I also have checked the orientation on the board. They are lined up correctly (see photo).

Mark

[MSL]

I ended up asking RJ for help and ended up sending it to him. He said he touched up a couple of my solder joints, flashed DMX and it worked.

To all that helped me with this EtherDongle, Thank you.

Now to get it working with LOR S3.

Mark

[tbone321]

Glad to hear that you got it working and that he had the time to help you.  If the man who designed it couldn't figure it out, then it would be beyond repair.  Unfortunately, there are some issues that are not easily determined second hand using pictures and guessing.