Discussion:
What are the NI-8451 SPI termination requirements for 5V Operation?
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JB_PTE
2008-05-22 17:40:14 UTC
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I'm looking to use the SPI interface of the NI-8451 to facilitate an automated characterization setup in my lab.  The slave SPI device that I will be using works on 5V logic. The users manual specifies using a minimum pull-up resistor of 1k for the static DIO lines to convert the 3.3V to 5V logic.  Can I use this same technique with the four SPI lines?  Also, figure 5 shows a resistive load to ground.  Is it necessary to have a pull down resistor to ground in addition to the pull up?
Sputnikrent
2008-05-23 21:10:07 UTC
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Hi JB, Yes you will should be able to use pull-up resistors to bring the SPI lines up to 5V. You will also need to have a pull down resistor to ground the way it is used in figure 5. Hope that helps!
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