---
title: "w5500 module with green led on without cable connected"
url: "https://maker.wiznet.io/forum/14731"
markdown_url: "https://maker.wiznet.io/forum/14731/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "heins"
created: "2022-11-30T23:27:23+09:00"
last_activity: "2022-12-07T18:30:03+09:00"
language: "en"
views: 468
replies: 15
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# w5500 module with green led on without cable connected

## Question

Asked by heins on 2022-11-30 in Ethernet Chips.

hello everyone, I have a w5500 module, but it happened to stop working, and I noticed that when I remove the cable, the green light is still on, any idea of ​​a damaged component?
what I suspect is that the end of the lan cable wet on the router and caused a short!

## Replies

### Reply 1 by Eugeny, 2022-12-01

Remove cable from the W5500 end having RJ-45 jack unplugged?

### Reply 2 by heins, 2022-12-01 (in reply to reply 1)

when i remove the rj45 cable the light stays on!

### Reply 3 by Eugeny, 2022-12-01

The question was about at which end you remove cable from the connector. Is it W5500 end (W5500 module connector), or router end (router’s connector)?

### Reply 4 by heins, 2022-12-01

end of w5500

### Reply 5 by Eugeny, 2022-12-02

Ok, green LED is usually link LED. It is lit when chip sees the carrier on the RX lines. After you remove the cable, what PHYCFGR reads? Next question, if you power cycle (turn off and he on) the device wiht W5500 does it start working, or still has green LED on and not working?

### Reply 6 by heins, 2022-12-02

Eugeny:

> o que PHYCFGR lê

Could you give me a light on this, I’ve been using it for a short time, yes the led is still on

### Reply 7 by Eugeny, 2022-12-03

[Datasheet](https://docs.wiznet.io/img/products/w5500/w5500_ds_v109e.pdf), page 42. W5500 will show you what it thinks about the link and PHY status in general.

### Reply 8 by heins, 2022-12-05

Eugeny:

> PHYCFGR

when I call the function getgetPHYCFGR() it returns me 0xff in hex,
however, even trying to set the register to 0xD8 with the setPHYCFGR() function, nothing happens.

### Reply 9 by irina, 2022-12-05

I think there is a problem with the chip, so SPI communication itself may not work.
Could you please read the VERSIONR register?

VERSIONR (W5500 Chip Version Register) [**0x0039**]
VERSIONR always indicates the W5500 version as **0x04.**

### Reply 10 by heins, 2022-12-06

when I call the readVersion() function it also returns me 0xff in hex

### Reply 11 by Eugeny, 2022-12-06

Surely SPI does not work as [@irina_kim](https://maker.wiznet.io/u/irina_kim) suspected.

Can you please look at [this](https://forum.wiznet.io/t/topic/10481/11) and check power supply for your device to ensure it is not the cause of weird issues.

### Reply 12 by heins, 2022-12-06

I think this is not the problem, because I removed the module from my board and I am testing it on an arduino uno and the same problem occurs, on the main board I communicate with an avr2560 and for the w5500 I have a linear regulator as1117 3.3v for it, being able to provides up to 1000mA, it always worked well, what I suspect is that the connector on the side of the router got wet, causing a short and damaging the w5500 chip

### Reply 13 by Eugeny, 2022-12-07

I am out of ideas.

The first thing is to use magnifier/microscope and examine module if there’s some physical damage.

The second thing you can do is proving that device driving the SPI does it properly (check with datasheet for SPI protocol for W5500). If you are sure AVR2560 does it right, but module does not respond (with 0x01, 0x02 and 0x03 while performing the SPI request) then module had died.

Answering your original question - I believe wet cable can’t damage the module, unless it is so wet and salty to short circuit or create unexpected currents (spilling onto the module or transformer).

### Reply 14 by heins, 2022-12-07

is there any way to reset the chip, either by software or hardware

### Reply 15 by Eugeny, 2022-12-07

Chip has hardware reset pin, and it must be operated after power up is complete (see datasheet for the reset timing). There’s software reset bit in MR register. I always perform software reset after hardware reset (the difference is not documented therefore I do both).

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Source: https://maker.wiznet.io/forum/14731