We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

Showing results for 
Search instead for 
Did you mean: 
Observer andrei.tunea
Registered: ‎04-09-2013

KCU105 pushbutton crazy behavior

Dear community,

I think there‘s something wrong with my KCU105. The board was used by some colleagues before and they reprogrammed the maxim power controller.

The behavior I‘m getting is this: one of the pushbuttons GPIO_SW_x connected to one of the LEDs. As simple as that. When I press the button the LED doesn‘t turn on. Sometimes it flashes. So I looked at the signal controlling the LED with an oscilloscope. While I press the button, instead of delivering a continous high-state to the led the fpga sends some erratic pulses....on this specific board kcu105 the pushbuttons are also connected to the zynq system controller. I read out their state using the UART commands and I seem to get correct info about the pushbutton state this way.


Why does the FPGA not pass on the state of the button to the LED? Has someone else seen this behavior before?

0 Kudos
2 Replies
Scholar drjohnsmith
Registered: ‎07-09-2009

Re: KCU105 pushbutton crazy behavior

cause and effect, seems to be that after the board was changed , the button function changed,

Put the board back to the way it was made, and see what happens
<== If this was helpful, please feel free to give Kudos, and close if it answers your question ==>
Observer andrei.tunea
Registered: ‎04-09-2013

Re: KCU105 pushbutton crazy behavior


yesterday I had a look at the power rails with PMBUS and with a multimeter. The VCCIO of the bank to which the LEDs and pushbuttons are connected has a voltage of 0.16V (PMBUS measurement). When we measure the votlage with a multimeter we get 2.3 V. The target VCCIO is 1.8 V.

Seems like something is wrong with the board. I'll see if I can get it configured right again.