LAN8720A Issues (SOLVED)

[lpcware]

Content originally posted in LPCWare by jnewell on Mon Sep 09 08:15:57 MST 2013
Hello, I'm just wondering if anyone out there has created a custom board with a LAN8720A.
I'm having problems with getting the 25MHz crystal to run.
I have attached the schematic that I am using.

Any Help/info would be appreciated.

Thanks,
Josh

[lpcware]

Content originally posted in LPCWare by MikeSimmonds on Tue Sep 10 16:42:20 MST 2013
For what it's worth, this is the ethernet part of our custom PCB. It is working.
Please don't ask me about it as I am not a hardware guy -- I do the firmware.

BTW, read the LAN8720 about mode etc. settings and compare with the pullups
and pulldowns on the schematic.

PS. We are connecting to an LPC1778 (208 QFP) so some of the CPU labels may
need translating for whatever chip that you are using.

PS. I think the forum reduced the jpg by about 19% -- Oh well!

Hope this helps, Mike

[lpcware]

Content originally posted in LPCWare by jnewell on Mon Sep 09 08:37:42 MST 2013
Also, I have noticed that at the VDDCR pin I am reading a voltage of 2.0V. According to the datasheet the internal regulator should be outputting 1.2V. Not sure why I'm getting 2.0V, any ideas?

-Josh

[lpcware]

Content originally posted in LPCWare by jnewell on Mon Sep 09 08:26:13 MST 2013
Yes I sure have,

I have an RDB1768 eval board (LPC1768 + LAN8720A) that I based my design on, and the schematic is pretty much the same besides the bead separating the analog 3.3V from the main 3.3V power rail (the PHY_A3V3 that is supplied to VDD1A and VDD2A). This shouldn't be an issue, though.

Thanks,

[lpcware]

Content originally posted in LPCWare by capiman on Mon Sep 09 08:22:24 MST 2013
Hello Josh,

have you already googled for "LAN8720A NXP". Here is e.g. one hit:

http://www.element14.com/community/servlet/JiveServlet/download/38-106658

I think also some LPCXpresso have the LAN8720A on board?

Best regards,

Martin