LPC Microcontrollers中的主题 Re: LAN8720A Issues (SOLVED)

LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:05 GMT

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

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:06 GMT

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

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:07 GMT

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,

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:07 GMT

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

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:08 GMT

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

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:08 GMT

Content originally posted in LPCWare by jnewell on Thu Sep 12 07:16:41 MST 2013

I figured out the reasoning for the 1.2V reading at 2.1V. It ended up that the ground pad on the LAN8720 wasn't getting a good connection.
Unfortunately it still isn't working although the correct voltage is on VDDCR.

Thanks Mike for the reference

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:09 GMT

Content originally posted in LPCWare by MikeSimmonds on Fri Sep 13 23:01:09 MST 2013
I seem to remember that the PXB designer had to put several vias under the
LAN8720A MLF package -- either for ground plane reasons or heat disapation
or both.

This level of detail is way over my head, but may make sense to others.

Cheers, Mike

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:10 GMT

Content originally posted in LPCWare by jnewell on Mon Sep 16 06:00:14 MST 2013
That is definitely the reason, one single via just does not cut it!

Anyway,Its connecting up to my switch, and showing activity. Only thing is, it won't receive anything tcp/udp. It sends out udp just perfectly(according to wireshark). Not exactly sure why. I'm also not able to ping or telnet into it.
Kinda stumped again, thinking I might have my receive lines backwards (not using an Ethernet connector onboard, just splicing it into a ethernet cable with 2 twisted pairs from the lines that come out of the magnetics).

Has anyone else ever had this problem?

-Josh

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:10 GMT

Content originally posted in LPCWare by capiman on Mon Sep 16 06:05:50 MST 2013
> Only thing is, it won't receive anything tcp/udp

Do you receive something at all?
Can you create a wireshark trace and upload it here?

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:11 GMT

Content originally posted in LPCWare by jnewell on Mon Sep 16 06:41:57 MST 2013
Well here is my wireshark capture. I've got the software sending 5 udp messages to a multicast server (239.0.0.0). I am definitely receiving the messages that are sent, on my server program.
I ran the ping right after packer 2206 appeared, and there is nothing.

-Josh

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:11 GMT

Content originally posted in LPCWare by capiman on Mon Sep 16 06:49:14 MST 2013
But there is also no ping in your screenshot, so your PC is not sending the ping?
Have you tried if you are receive something (does not matter what) on your LPC?
Usually there are broadcasts, ARP, ... which the LPC receives? Does it?

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:12 GMT

Content originally posted in LPCWare by jnewell on Mon Sep 16 07:45:41 MST 2013
I've tried a few things, nothing is received by the LPC.

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:13 GMT

Content originally posted in LPCWare by jnewell on Mon Sep 16 12:53:07 MST 2013
Well, I hooked back up my RDB1768 Eval board, to compare the output of Wireshark, and here's what I got. It pings just fine, and also connects to telnet just fine.
I'm thinking that there is just something the PHY doesn't like about my custom schematic still.

-Josh

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:13 GMT

Content originally posted in LPCWare by MikeSimmonds on Mon Sep 16 21:54:57 MST 2013
For your wireshark filter, try "ip.addr == xxxxxx or arp"
to confirm your board handles arp correctly.
Here is a capture for my setup.

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:14 GMT

Content originally posted in LPCWare by MikeSimmonds on Mon Sep 16 22:06:13 MST 2013
Is the emac code exactly the same on the Code Red eval board and your custom board?

I had to reverse the MAC address when I put it in the EMAC 'Station Registers'
(the user manual has a section that is complete and utter bullsh1t!)
Also, in the receive fiter register, set multicast AND broadcast -- one is a superset
of the other, I can't remember which way round -- as well as unicast.

You do know that if your board dosn't answer ARP broardcasts that the other end will
not send the ping echo request (or udp or tcp) don't you.

Finally, in your receive interrupt, recheck for received packets till all are seen.
Otherwise you will miss packets and never be in sync.

Cheers, Mike

Clarification, i.e. NOT reverse the MAC addr like the manual claims you must!
'Reverse' above means oposite to what the UM10470 says!

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:15 GMT

Content originally posted in LPCWare by capiman on Mon Sep 16 22:10:48 MST 2013
@Mike:
Can you give me a reference in which User Manual (which LPC)
this error/the wrong section is?

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:15 GMT

Content originally posted in LPCWare by MikeSimmonds on Mon Sep 16 22:22:44 MST 2013
UM10470 rev 2.1 (6-Mar-13) section 10.7; figure 22 is false to fact!
MAC addresses are transmitted oct1m oct2, ... oct6
This is shown by the dumps in wireshark and in packet dumps in my
firmware in the debugger.

E.g: my board;s MAC is 00:04:A3:3B:D7:C6

[Code]
movsr1, memBase; get MAC addr from eeprom cache
ldrhr0, [r1, eMac+4]; last 2 digits ABCD[EF]
strr0, [r7, netMacAddr0];
ldrhr0, [r1, eMac+2]; middle 2 digits AB[CD]EF
strr0, [r7, netMacAddr1];
ldrhr0, [r1, eMac+0]; first 2 digits [AB]CDEF
strr0, [r7, netMacAddr2];

movsr0, 0x26; unicast/multicast/broadcast
strr0, [r7, netRxFltCtrl];
[/Code]

Note how the valuses are in reverse order to the EMAC registers!

Cheers, Mike

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:16 GMT

Content originally posted in LPCWare by capiman on Mon Sep 16 23:13:54 MST 2013
I think figure 22 looks ok. Or have I overseen something?
When just comparing the values of figure 22 against a wireshark trace, I think the both are consistent,
e.g. DesA oct 6 is transmitted first in packet and also in wireshark decoding of address.
Is it perhaps a problem what is assumed as first byte (the MSB or LSB)?

What i haven't looked at: Are perhaps Station Address Register SA0,SA1,SA2 not consistent to figure22?
So is the value you write into SA0 Bit 15:8 really the oct1 mentioned in figure 22.
Is this what you mean, that there is an error?

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:17 GMT

Content originally posted in LPCWare by MikeSimmonds on Tue Sep 17 00:27:57 MST 2013
The UM figure clearly shows 'octet 6' being transmitted first.
for my MAC address, that is 'C6' (The sixth byte of the address.)
Wireshark and the debugger show the first byte sent or received is
'00' followed by '04' then '3A' etc. with 'C6' last.
See atached snap.

Hence figure 22 is wrong by my reckoning.

I know the each BYTE is transmitted LS BIT first, but the bytes are
transmitted in first to last order. [At least, that is how they end
up in memory.]

And you can't get away from the fact that the fith and sixth bytes of the
MAC address have to be put is Station Register ZERO to make it work.

What say you? Mike

Re: LAN8720A Issues (SOLVED)

lpcware — Wed, 15 Jun 2016 18:11:17 GMT

Content originally posted in LPCWare by capiman on Tue Sep 17 00:47:26 MST 2013
I think i agree with you!

But just in case if NXP has counted the other way round:
Then UM figure 22 would be ok, because our first byte is their last byte?
And the value you put into Station Register ZERO is byte zero and one, so correct order?