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enc28j60 not stable
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Date: 2006/05/28 07:24
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By: Genady
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Status: Visitor
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Hello to everybody.
Does somebody have problem like mine ,which is that my web working fine at start and then after some time (i think the problem is in enc28j60) i see that same paghes which i call before takes more time to explore ,so i check how much takes to reply my pings with my ip and i see that the time at start was 2 or 3ms and now the time is not stable and reaches up to 2s ,.
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Re:enc28j60 not stable
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Date: 2006/05/28 08:53
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By: Ian
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Status: Moderator
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Karma: 5
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| Posts: 85 |   |
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Read the errata, there is an issue with the silicon, todo with clock speeds. The SPI clock needs to be at least 8Mhz for stablility.
I will try and post a solution article when I have the time.
Ian
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Re:enc28j60 not stable
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Date: 2006/05/28 09:33
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By: Genady
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Status: Visitor
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Ian i read errata and i am working with pic 18f8722 and my spi frequency is 10Mhz
so this is not a problem .
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Re:enc28j60 not stable
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Date: 2006/06/03 13:25
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By: ehaluk
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Status: User
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Karma: 0
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| Posts: 1 | |
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Hi Ian, i have also same problem.I dont know how it is, ENC first works then doesnt work and sometime it is Ok but then it if off .It is not stable. I use 18f4620 with 10Mhz crystal HS-4XPLL and i am sure my board's hardware is ok.I think SPI clocks is not stable but why? Help pls. 
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Re:enc28j60 not stable
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Date: 2006/06/15 10:19
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By: Ian
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Status: Moderator
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Karma: 5
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| Posts: 85 | |
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I had a similar problem at one point, but haven't figured out why.
I'll keep looking into it.
Ian
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Re:enc28j60 not stable
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Date: 2006/06/19 01:45
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By: asmallri
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Status: User
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Karma: 2
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| Posts: 5 | |
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I have had the ENC28J60 running stable for a few months so it can be done.
If you are using the MCHP stack then make sure you have the latest version of the stack that includes the bug fixes for ENC28J60 Errata B4.
If you are using "roll your own" hardware check that you have used the correct pinouts for the RJ45 for your specific model connector. There are multiple RJ45 with embedded magnetics on the market and most ARE NOT interchangeable because of different pinouts.
A commmon problem with "roll your own" hardware implementations is the transposition of the receive wires or the transmit wires (+ to -). The ENC28J60 is meant to be able to handle this but it cannot.
If you have modified MCHP sample code then do not forget that their implementation is a cooperative multitasking statemachine approach. If you PIC code "is doing other stuff" then the Ethernet logic does not get processed. If you are "doing other stuff" too long then the receive buffer space on the ENC may fill and the ENC will discard packets. If you are on a busy network segment, one with lots of broadcast and multicast traffic, then it is easy to overrun the receive buffers. This then requires the upper layer protocols (TCP and above) to attempt recover after timers have popped etc.
MCHPs stack is a great starting point but if you want a performance or need a reliable, deterministic production system, it is not good enough - you need to determine what is the minimal set of network functions required to meet your applications requirements. For example, using a web brower from end to interface to a PIC great for proof of concept demo etc but naturally it assumes a human at one end of the link. If you want machine - to - machine interface then there is no way you would add the complexity of a HTTP stack implementation just to set and get a few data points.
I think MCHP have provided a good prototyping tool with their stack.
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