---
title: "Spi"
url: "https://maker.wiznet.io/forum/10275"
markdown_url: "https://maker.wiznet.io/forum/10275/md"
type: "Forum topic"
category: "Wireless"
author: "mikenum"
created: "2014-06-01T19:23:15+09:00"
last_activity: "2017-05-04T08:33:03+09:00"
language: "en"
views: 457
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Spi

## Question

Asked by mikenum on 2014-06-01 in Wireless.

Hi,

I have several questions about SPI interface:

Q1: How many data bits shall I use when talking to WizFi250 via SPI ?
Q2: Can I make burst data transfers with a single SPI_SS assert on or shall I toggle SPI_SS on every data transfer? It would be good to see examples of the waveforms somewhere in the datasheet.
Q3: Here [wizwiki.net/wiki/doku.php?id=pro … escription](http://wizwiki.net/wiki/doku.php?id=products:wizfi250:wizfi250ds:4.pindescription). What pin is used as SPI_DATA_READY output?

Thanks in advance for your help!

## Replies

### Reply 1 by kaizen, 2014-06-01

Hi

Q1: How many data bits shall I use when talking to WizFi250 via SPI ?
[color=#FF0000]A1: WizFi250 support to send and received 1byte data after SPI_SS is set low.[/color]

Q2: Can I make burst data transfers with a single SPI_SS assert on or shall I toggle SPI_SS on every data transfer? It would be good to see examples of the waveforms somewhere in the datasheet.
[color=#FF0000]A2: Yes, WizFi250 is not supported burst data transfer with a single SPI_SS. So WizFi250 have to toggle SPI_SS on every data transfer. Please refer to this example source code. ( [url][https://github.com/Wiznet/Arduino_WizFi250\[/url\]](https://github.com/Wiznet/Arduino_WizFi250%5B/url%5D) )
[/color]
Q3: Here [wizwiki.net/wiki/doku.php?id=pro](http://wizwiki.net/wiki/doku.php?id=pro) … escription. What pin is used as SPI_DATA_READY output?
[color=#FF0000]A3: SPI_DATA_READY pin is GPIO14. we modified wiki page.[/color]

### Reply 2 by mikenum, 2014-06-02

Great! This helps a lot, especially the source code! One other question though: what is maximum SPI clock frequency allowed?

### Reply 3 by kaizen, 2014-06-02

Hi

WizFi250 can use spi clock up to 2.25Mbps. But WizFi250 can’t use full speed of spi clock due to the fact that WizFi250 is not supported burst data transfer with a single SPI_SS.

---

Source: https://maker.wiznet.io/forum/10275