Cable not detected

Question

I notice that when I read the PHYSR.CABOFF bit (0x003C), it always returns “Cable unplugged” (1). This is the case when I plug or unplug the cable. I run the IOLibrary DHCP software, so the 5100S has been configured. Should the CABOFF bit always read 0 when I plug the cable, or should I do something more (the other side of the cable is connected to a router) When I plug in the cable, should one of the connector LEDs light up? We designed our schematic just like the reference design. Thank you in advance, Daan

Eugeny · Answer

Daan: or should I do something more (the other side of the cable is connected to a router) Of course. Connection detection is performed using sensing electricity in the wire, not sensing physiscal insertion of the cable. Daan: When I plug in the cable, should one of the connector LEDs light up? If there’s another active device at another end of the cable.

Eugeny · Answer

Daan: should I configure some register in the software to have the LEDs light up I do not think so. If PHY is up it must turn at least link LED on. Does the switch light its link LED up? So the things to check are cable (try another one), circuit diagram (check again - did you use parts from reference or replaced some with another parts?), and assembly quality (missing some ferrite beads?). Would be good if you share your actual circuit diagram here.

Daan · Answer

I have already tried another cable and checked the PCB, all looks OK. I can read the W5100s registers, so the interface between CPU and Wizchip is OK. The 25MHz xtal is running and all 1.2 and 3.3 voltages are correct. The router doesn’t light up any LED either. I attached our schematic . afbeelding1195×809 65.9 KB

Daan · Answer

This is the jack (Wurth 74990111217): afbeelding530×539 20 KB

Daan · Answer

Bead (Wurth 742863160): 600 ohm, 500 mA, WE-CBF HF Series, 0.35 ohm, ± 25%

Eugeny · Answer

Daan: This is the jack (Wurth 74990111217): The problem could be in your wiring pins of jack wrongly, that’s why for circuit diagram pin numbers are the MUST. It will also assumes that you wired device properly at the device editor level.

Daan · Answer

Yes, that could have been the cause, but we have checked the connector layout and it is OK. Our hardware engineer has inserted the pin numbers: afbeelding1463×767 53.7 KB

Daan · Answer

Do you have any other suggestion?

Daan · Answer

This is my initialisation: uint8_t mr2; CHIPUNLOCK(); mr2 = (uint8_t)getMR2() | 0x80; // MR2_CLKSEL; setMR2(mr2); CHIPLOCK(); PHYUNLOCK(); setPHYCR0(0x02); setPHYCR1(0x01); PHYLOCK();

Daan · Answer

The reset circuit is designed to give a high level after 1.53ms. The datasheet describes this should be 210ns minimum. Could you please explain what is wrong with our reset circuit? Why is a MCU pin better than an RC-circuit?

Daan · Answer

We see some noise on the 1.2V supply, please see the scope screenshot: afbeelding1024×768 25.2 KB Could this noise do any harm? The 3.3V supply is stable and clean.

Daan · Answer

The supply circuit is as shown: However, we removed and shorted L2 with a wire. C15 is now 10uF and parallel to C5 is another capacitor of 2.2uF ro reduce the noise. All capacitors are ceramic.

Daan · Answer

Thank you for your hints so far! I now generate a clear digital reset pulse to the W5100s. When I read back the link bit of PHYSR, it is always 0, also after a reset pulse, which I can run manually. However, the datasheet is not clear how long the reset pulse should be: It should be between 210 and 560 ns

Daan · Answer

However, the pin description says it should be > 500ns: How long should the reset signal be, minimum and maximum?

Daan · Answer

We found the problem! There is an error in the reference design: TCT and RCT of the ethernet jack should be connected to 3.3V, this is indicated in the evaluation board schematics, but not in the reference design. After applying this patch, everything worked perfectly.

Edward · Answer

Hi Daan and Eugeny I’m really sorry about that. I posted the wrong w5100s reference schematic. Then I was modified to the schematic. please refer to wizwiki.net and new w5100s reference page. (W5100S_ext_Ref_Schematic_V110) https://wizwiki.net/wiki/doku.php?id=products:w5100s:refschematic Thanks

Eugeny · Answer

midnightcow: The reset time should be 560ns because W5100 can be reset in the wors case. You mean minimum 560 ns? Can I have reset time of 100 ms?