Connect Digital In to +5V FPGA

[LVD]

Hello,

I have a small (maybe stupid) question about connecting a Digital In signal of an external driver board to an FPGA I/O.

There is a Digital Input pin on the driver board that should always have the value "1", and it should obtain this value before anything else happens on the driver board. So I thought the easiest solution is to connect the pin directly to the 5V output of the FPGA.

The actual output of the 5V is 5,11V. So the board will associate this value with a digital 1. But the other I/O connections of the FPGA generate only 3,3V for a digital 1. WIll this give any problems on the driver board? I haven't found anything about this in the driver manual. Maybe someone with electrical experience may know this answer? In case someone would like to know, the driver board is a TMCM-090 from trinamic.

With regards,
Dries

[Christian Mergl]

First of all, if you have a question related to hardware, you should tell us which hardware you are using!

I assume it's a PCI-78xx board.

The 5V you are talking about is the power supply from the motherboard and is not related to the 3.3V level at the DIO Pins of the FPGA.

Christian

[LVD]

It is a PXI-7842R.

[Christian Mergl]

Same behaviour, just that the 5V are from the PXI backplane.

Btw, the DIO Lines are protected between -20V and +20V

Christian