---
title: "Cable Detection Process for W6100 Chip"
url: "https://maker.wiznet.io/forum/15147"
markdown_url: "https://maker.wiznet.io/forum/15147/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Jiri Jasek"
created: "2024-02-12T13:54:00+09:00"
last_activity: "2024-10-29T21:09:37+09:00"
language: "en"
views: 127
replies: 2
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Cable Detection Process for W6100 Chip

## Question

Asked by Jiri Jasek on 2024-02-12 in Ethernet Chips.

We are currently working with the **W6100** chip and would like to understand the process for detecting a connected cable.

For some connection the chip seems not to be able to detect connected cable.
For detection we are using the PHYCFGR register and bit 0.

Sometimes it doesn’t detect the connected cable, and since then it cannot detect any connection, even if connected to previously working router. This status persist till repower of device.

Schema of our connection:

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/0/097f1571a7d461264b009a1a268d655723aa52cc.png) image1213×748 82.9 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/0/097f1571a7d461264b009a1a268d655723aa52cc.png)

## Replies

### Reply 1 by Eugeny, 2024-02-13

Power quality? Does power supply have enough rating? Why 1k resistors on reset and int lines? Are you able to read registers when issue happens? Does it recover if you disable/reset PHY using PHYCFGR? What is the value of PHYCFGR before, when it works, and after, when it locks up? What is part number for L11/L12? Check for components values at the PHY side.

### Reply 2 by al_bin, 2024-10-29 (in reply to reply 1)

I have the same problem with W5500 EVB Pico. I can read the registers when the problem occurs. PHYCFGR reading is correct 0xBF several dozen times, followed by one 0xBA, as if the cable was disconnected. And so on. Disconnecting the ethernet does not help, the power supply pulse does. Afterwards, the device continues to operate until the power supply fails. The device turns on correctly 9/10 times.

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Source: https://maker.wiznet.io/forum/15147