Link LED

Question

I am new to TCPIP and I am figuring it out as I go. When I power up the W5500 chip with no micro connected should the link LED come on when an ethernet cable is plugged into the RJ45 jack. The cable has been tested with other products and is good. I am not getting the link LED on when I plug in a cable, what would commonly cause this if it is abnormal.

Coccoliso · Answer

Hi, I think you are referring to a standard WIZ550IO module… If so you have two LEDs (watching cable socket) one yellow on the bottom right and one green on the bottom left side. Powering the module (without MPU and without resetting the module) without cable attached is all off. When you insert the cable, the yellow LED is steady on and waiting a few seconds the green starts flashing (when router start to try a communication with it). Please note that at this point IP is no set and MAC address is almost certainly random since you have to set it after a reset. While under normal conditions (with MPU connected that drive the W550IO) little change, the yellow LED is always on with the cable connected while the green LED flashes more frequently (we say that there is more movement).

TonyR · Answer

Thank you for the reply I have a W5500 chip on a custom board We are not using the module at this time. It is just the W5500 with no SPI connections. I am giving the chip power and plugging in the cable to the RJ45 jack. I was told to expect the link led to turn on, it does not. I understand there is a Micro controller on the module, I do not have one. So the chip is not configured, no MAC, nothing.

TonyR · Answer

It was suggested that I should include a schematic snippet for everyone to look at. From the W5500 to the magnetics chip is from the sample schematic. From the magnetics chip to the RJ45 is like the integrated magnetics in the J1B1211CCD. I am seeing the link pulse at the magnetics chip. 1713×838 213 KB Thank you for your time and effort to review this for me and answer the question of if the W5500 will pull pin 25 low when a cable is plugged into theRJ45 connector even when there is no micro controller commanding it.

Coccoliso · Answer

Hi, the only thing comes to mind that can help you is the diagram of the module that hosts it (although maybe you left from there) [url]http://wizwiki.net/wiki/lib/exe/fetch.php?media=products:wiz550io:wiz550io_v1_2_schematic.pdf[/url] but we can not know what the PIC12F519 sends to W5500 before moving from his MOSI_A to MOSI_B on external MPU SPI If we could have the source about it it would not be very bad.

lawrence · Answer

Hello, TonyR Thank you for your interest with W5500. I suggest to refer the below schematic. [url]http://wizwiki.net/wiki/doku.php?id=products:w5500:refschematic[/url] It will help you, thank you lawrence

TonyR · Answer

Thank you Lawrence, I saw that after discovering this issue or I would have used that schematic. I do not think the problem lies in the schematic from the magnetics chip to the connector because the resistors are identical to what is found inside the recommended connector (J1B1211CCD) with integrated magnetics. I am attaching a jpg of the internal schematic for the connector so you can see that I am honoring a valid approach. I will probably switch to the schematic you shared with the next layout. I suspect there is a register on something that the microcontroller on the module does that I am not aware of and we are not honoring. 1577×867 136 KB

TonyR · Answer

[quote=“Coccoliso”]Hi, the only thing comes to mind that can help you is the diagram of the module that hosts it (although maybe you left from there) [url]http://wizwiki.net/wiki/lib/exe/fetch.php?media=products:wiz550io:wiz550io_v1_2_schematic.pdf[/url] but we can not know what the PIC12F519 sends to W5500 before moving from his MOSI_A to MOSI_B on external MPU SPI If we could have the source about it it would not be very bad.[/quote] I am hoping that someone will share that information. Thank you.

TonyR · Answer

Found the problem. It is a schematic oversight on my behalf. R16, R17, R18 are supposed to have a connection to 3.3v to bias them. I missed it. Thank you for the help everyone.

lawrence · Answer

Hello, TonyR Very happy with your good news. Always welcome any issues or comments. Thank you, lawrence