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EMX Digital IO Pin State at Power-up


#1

I’ve got an application that has two digital IO pins, IO9 and IO26, driving transistors which control relays. In the EXM User Manual these pins are listed as general purpose digital I/O without any other 2nd functions.

At power up these go pins go high until my application takes over and returns them low. Is there any internal control or setting in the EMX that would, at power-up, have these in a low state? Having the relays bounce high at power-up is not the preferred mode for my application.

Thanks


#2

you have to throow a pull down resistor in on each pin to keep the on high setting from effecting you.


#3

Is this the same problem I’m having on my EMX board. I’m wanting pins IO46, IO45, IO47, IO7 and IO6 to read voltages. The last four are fine, floating around zero when unconnected, but IO46 is consistently at 3.5 volts and I can’t seem to bring it down.

On my equivalent Cobra board all the pins quite happily float around zero. And I’m pretty sure when I first read from the EMX pins there wasn’t this one pint set to high.

Have I somehow forced this pin high? Is this possible? Can I do a pin re-set to get them back to normal?


#4

All pins are inputs with pull up resistors on power up if they are not connected. Check the schematics please