Realtek 8019AS + PIC18 Problem

Nikhil Patil 22 years ago

Hi,

We have interfaced a Realtek NE200 clone (RTL8019AS) with a microchip PIC18F452. Our hardware has been mostly copied from the Microchip PICDEM.net board, and we are using the Microchip stack.

However we are facing a strange problem. We are not able to communicate with the NIC. If we request the MAC Address, for example, we get 10:30:50:70:90:b0 instead of 12:34:56:78:9a:bc.. ie the second nibble of every byte is always zero. We are using the NIC in 8-bit mode.

Could it be a problem of soldering? - we have two identical boards showing this same problem... Or could it be due to the oscillator being too close to the data lines? We are absolutely perplexed.. can anybody suggest ways to debug such problems?

Our layouts can be accessed at

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Any help will be highly appreciated!! Thanks, Nikhil Patil

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The real Andy 22 years ago

I have seen this problem before, and if I remember correctly, it is a known problem in the NIC chip you are using. Try google for a work around.

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Jeremy Bentham 22 years ago

I've done around 6 Realtek designs with various CPUs and MCUs, and have never seen this problem. If you copy the PICDEM.net properly, it'll work fine.

Jeremy Bentham Iosoft Ltd.

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Markus Zingg 22 years ago

Out of my (limitted) experience, such effects often point towards timeing issues with waitstates etc. Are you sure you are within the specs of the RealTek here?

Markus

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Brian Logan 22 years ago

It was a few months ago, but I seem to remember this is the same problem I had with an RTL8008 based ISA card. I was using the OpenTCP TCP/IP stack which wrote to some page 3 registers that don't exist on an original NE2000. Whether or not the RTL8008 implements these or not, I don't know. I couldn't get a data sheet out of Realtek. They said they couldn't find it on their FTP server! How about getting of your arses, guys!!! Anyway, although the RTL8019AS implements these registers, it might be a good idea to try and temporarily comment out any code that accesses page 3 registers to see if that helps.

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