WIZnet Developer Forum

Spi

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. What pin is used as SPI_DATA_READY output?

Thanks in advance for your help!

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. ( https://github.com/Wiznet/Arduino_WizFi250 )
[/color]
Q3: Here 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]

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

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.

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