Link not working

Question

I’m having trouble getting a link with W5200. I have made two boards and both cannot get a link when connecting an ethernet cable. I’ve made the schematic following the W5200 reference schematic. I’m using the RB1-125BAG1A MagJack. I’ve checked all hardware connections and SPI works good. I’m able to set MAC and IP etc. I read the PSTATUS register as 0x07 every second, with or without cable connected. What could be wrong?! Here a part of my schematic: 1512×868 35 KB Regards, Martijn

Eugeny · Answer

Martijn, you changed original circuit a little. LED part. Why did you change it? W5200 senses its mode using LED outputs in input mode, are you sure putting P-MOSFET will not affect proper mode identification? I assume you already saw reference schematic from [url]http://www.wiznet.co.kr/product-item/w5200/[/url]. Please stick to it as much as possible. pin 45 should be pulled down. If it is not, W5200 may power PHY down - probably this is what happens in your design. CS, INT and RESET should have pull-ups to have proper levels when master does not (yet) drive the bus. and finally, as you are able to read W5200’s registers, I assume you powered 1V8 properly.

Tinus81 · Answer

Hi Eugeny, thanks for your reply. I changed LED part because I need to drive more LEDs in the final product (which also will be PWM-ed). I desoldered the mosfets to test if that would work, but it doesn’t. I get no link. Yes I did. For example, the power supply part was a direct copy of reference schematic. Now with the added resistors my schematic is equal to the reference schematic. OK, I added a pull down resister to pin 45. OK, I added pull up resistors to these pins. Yes, I’m able to read and write registers. On the 1,8V pin I measure 2,09V, maybe it’s a little high? Even with the pull up and pull down resistors and removed mosfets I get no link. I’ve tested all w5200 pins, all are connected to the board ok. I’ve measured Auto Negotiation pulses on all the w5200 phy pins (17/18, 20/21), but only with an ethernet cable is connected. Without cable I don’t measure these pulses (shouldn’t the w5200 also send negotiation pulses?). I really have no clue where to look further or where the problem might occur Any ideas?? Thanks, Martijn

Eugeny · Answer

Tinus81: On the 1,8V pin I measure 2,09V, maybe it’s a little high? Not little, it is too high - 16% above nominal. Did you connect 1V8_OUT to 1V8D through ferrite bead with capacitors as recommended on reference circuit diagram (top right corner of the sheet)? My first guess that you have 2.09V simply because 1V8_OUT (regulator output) does not have any load.

Tinus81 · Answer

[quote=“Eugeny”] Not little, it is too high - 16% above nominal. Did you connect 1V8_OUT to 1V8D through ferrite bead with capacitors as recommended on reference circuit diagram (top right corner of the sheet)? My first guess that you have 2.09V simply because 1V8_OUT (regulator output) does not have any load.[/quote] Yes I did connect 1V8 out through ferrite bead and all the capacitors are there. I’ll check the board tomorrow and measure the 1V8D pins. Thanks for your help so far!

Eugeny · Answer

Yes, you surely need to check your board. I hope chip did not fry. Probably you have some shortage, for example pulled up RSV (7) is shorted with 1V8 (8).

Tinus81 · Answer

I’ve placed a new w5200 on the board, to be sure it’s not defect. I’ve checked for shortage, there are no shortages. When I power up now, the 1V8 measures 1V9, so that seems much better. However I still get no link… I’ve tried multiple network switches and cables by the way. Any other suggestion??

Eugeny · Answer

Can you please post a photo of your board from both sides? Did you connect 3V3A to 3V3D through recommended circuit? You did not provide full circuit diagram related to W5200, thus I have to guess what is out of the image you posted. From what I see that digital part seems to work properly - XTAL, host-side I/O, PHYSTAT shows correct value, PHY is not in forced power down mode. Thus there’s most probably some issue at the TX/RX and/or magjack’s side.

Tinus81 · Answer

Here are photo’s from top and bottom side: 1920×1424 963 KB 1920×1424 936 KB The resistors connected with rework wire are the extra pull ups and pull down. Also, here is full schematic: Schematic.pdf (55.9 KB) I really appreciate your help!

Eugeny · Answer

In my opinion your circuit diagram is correct. Layout can be improved and optimized, but in general it should work. Do R5 and L3 have any shortage between them?

Tinus81 · Answer

You are my hero! The shortage should be there - but not with R5. It turns out that the text of R5 and C21 is reversed R5 is the bias resistor on pin 12. Thanks a lot!!