回复： Can I use DIO port of NI8451 as extra CS lines ?

[ERAspread]

Hi,

 I have 30 slave devices to communicate, but the USB-NI8451 only have 8 CS line. I am thinking I can use the DIO port as extra CS lines. 

Is that possible?

And then I can use two NI8451s to communicate with 30 slave devices .

[Crazywu]

I do not recommand this method. 

SPI is different from DIO which only has 1 and 0 signal.

You could have a better understanding of SPI Bus, DIO and I2C with below links.

https://www.ni.com/docs/en-US/bundle/virtual-bench-help/page/digital_io_toc.html

Understanding the SPI Bus with NI LabVIEW: https://www.ni.com/en/shop/labview/understanding-the-spi-bus-with-ni-labview.html

SPECIFICATIONS USB-8451 OEM：https://www.ni.com/docs/en-US/bundle/usb-8451-oem-specs/resource/290598a.pdf

Using I2C with LabVIEW and the USB-8451: https://www.ni.com/en/support/documentation/supplemental/21/using-i2c-with-labview-and-the-usb-8451....