Mesa 7I43-4 first tests but no sucess

Hi PCW

I know.. On other places in manual you write that pull-up can be switched on and of by SW.

I'm talking only of input-mode.

1K is not enough to get low signal.

There is an resting "offset" of 1.49 V. Means in my eyes that ca 1.5mA are driven by the board.
So pull up seems to be also in the range of 1K.

I want to use Input with floating pins.

How can I get that by hostmot2 ?

Mike

By removing the pull down resistors and following the high=inactive standard

That is to say the 7I43 (and all of our FPGA cards) are designed for
active low inputs and outputs, for output safety, OPTO22 compatibility and
compatibility with the FPGAs HotSwap/ preconfiguration mode.

This means its much easier to use active low I/O and use the built in pullups

Note that this same situation applies to parallel port inputs, they normally have built in
pullup resistors (the original IBM design has 4.7K pullups to 5V on the input pins)
which means pulldowns (unless they are very stiff) will lead to marginal I/O voltages