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Topic: Mighty 1284p SPI / Ethernet how to get it work ? (Read 3 times) previous topic - next topic

Nick Gammon

Well there is good news and bad news.

The good news is, I've reproduced your problem. :)

The bad news is, the fix is not totally working. :(

I hooked up my 1284P to my Ethernet Shield Rev 3, and found that (using the logic analyzer) although the signals were going out as expected, nothing was coming back.

Then I took a closer look and realized that the shield is designed to interface with the ICSP header (underneath) rather than pins 10/11/12/13 because it is designed to be plugged into other boards, like the Mega.

So I moved SCK, MISO, MOSI to the ICSP header.

Code: [Select]

       Atmega1284P    Ethernet Shield

SS     pin 5  (D4)      D10 on the shield
MOSI   pin 6  (D5)        ICSP pin 4
MISO   pin 7  (D6)        ICSP pin 1
SCK    pin 8  (D7)        ICSP pin 3

Now at least it got a response. But still rather flaky. It didn't hang on the connection any more. Just "failed".

I made the change I mentioned to the w5100.h file. I experimented with slowing down SPI:

Code: [Select]

  // start the Ethernet connection:
  Ethernet.begin(mac, ip);
  SPI.setClockDivider(SPI_CLOCK_DIV16);   // slow down SPI

It connected a couple of times, it got data back a couple of times. You may have more luck with your wiring. I think I have a lot of noise here, I am having trouble uploading the sketch.

This should get you closer.

Nick Gammon

Further to the above, it appears that during testing I crashed the server I was connecting to. So it might be more reliable if you implement all those changes. Maybe. :)


Was any solution to this ever found? I'm experiencing the same with 1284P. I tried both Calunium and Mighty1284 with the same result: a hanging 1284P when I call ethernet.begin(...)


I found that the issue only exists when attempting to use DHCP.


I just got back from summer hollidays, sorry for not giving back any infos soon after Nick sent his message about a fix. I did not had time to tried.
Really, only DHCP does that ? i tried both fixed IP and DHCP and the result was the same. IIRC last month test.

I found that the issue only exists when attempting to use DHCP.

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