---
title: "WizFi250 UART / SPI selection issue"
url: "https://maker.wiznet.io/forum/14619"
markdown_url: "https://maker.wiznet.io/forum/14619/md"
type: "Forum topic"
category: "Wireless"
author: "Sebastian"
created: "2022-08-22T14:42:09+09:00"
last_activity: "2022-09-27T00:13:30+09:00"
language: "en"
views: 375
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# WizFi250 UART / SPI selection issue

## Question

Asked by Sebastian on 2022-08-22 in Wireless.

Hello,
I am using the WizFi250 with the SPI interface only. This works but on rare occasions the module will reboot. I was finally able to track this down to the WizFi250 receiving HF noise on the open UART RXD pin. Then it thinks a character was send on UART and reboots. I can prevent this by wiring the RXD pin to ground but would like to know is there is a software solution so it will ignore the UART completely as we have maybe 1000 WizFi250 in the field and adding a ground wire to all of them would be quite a mess… Setting AT+MSPI=2 does not seem to make any difference. Firmware in use is 1.0.3.3.

Thank you!
Sebastian

## Replies

### Reply 1 by austin, 2022-09-05

Hello [@Sebastian](https://maker.wiznet.io/u/sebastian)

As mentioned to us, there’s no way to set SPI/UART interface other than ‘AT+MSPI’ AT command.

Therefore, it should be solved by fixing H/W.

I’m sorry I couldn’t help you.

---

Source: https://maker.wiznet.io/forum/14619