---
title: "W5500 MISO Signal Attenuated"
url: "https://maker.wiznet.io/forum/14268"
markdown_url: "https://maker.wiznet.io/forum/14268/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "JustDavid"
created: "2021-06-17T15:17:44+09:00"
last_activity: "2021-06-28T07:14:12+09:00"
language: "en"
views: 404
replies: 5
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 MISO Signal Attenuated

## Question

Asked by JustDavid on 2021-06-17 in Ethernet Chips.

I am having trouble with my W5500 circuit.
The clock, CSn, MOSI (Shown as channel 2) look great but MISO (shown as channel 1) is coupling with the CLK and is severely attenuated. I connected a 560pF cap from MISO to GND to reduce the coupling but the attenuation hasn’t changed. The net looks clean, no shorts to others.

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/1e5ba4912fe5338541b2f47f326e746ed2828517.png) image1024×630 61.1 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/1/1e5ba4912fe5338541b2f47f326e746ed2828517.png)

Closer:

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/2/233e95d355388e67ef152b48f9d16baaf586d7c5.png) image1024×630 54 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/2/233e95d355388e67ef152b48f9d16baaf586d7c5.png)

When I cut the trace to the Nordic nRF the signal doesn’t change.
Changing the SPI transmission speed makes no difference.

Any ideas?

## Replies

### Reply 1 by bruno, 2021-06-21

Hello

Please show me the schematic for verification

### Reply 2 by JustDavid, 2021-06-21

[![image](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/9/98e897e27187a7a8fcc7ff141e222b240696c349.png) image944×755 15.1 KB](https://maker.wiznet.io/forum_uploads/wiznet/original/2X/9/98e897e27187a7a8fcc7ff141e222b240696c349.png)

### Reply 3 by bruno, 2021-06-22 (in reply to reply 2)

Sorry but the image you posted looks blurry.
So I can’t understand the schematic you posted.

### Reply 4 by JustDavid, 2021-06-22

[504-P10003 Rev A Schematic.pdf](https://maker.wiznet.io/forum/legacyFile.asp?path=u0g7SLHs0pJqMGjJVSO6oLb8ULW.pdf) (447.8 KB)

### Reply 5 by bruno, 2021-06-28 (in reply to reply 4)

I’ve looked through a lot of stuff, but I couldn’t find a problem with the SPI circuit.
And there was no SPI-related issue that W5500 inquired about.
Sorry for not being of any help.

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Source: https://maker.wiznet.io/forum/14268