Difference between JP4 and JP6 on digital output

[xuphoenix]

Based on the manual, IO16-23 and IO26-33 should be the same as digital outputs. But when I directly connect the digital pins and GND to a multimeter to measure the output voltage, IO16-23 gives 1.74V while IO26-33 gives 2.99V. Is my KFlop broken? I'm using KFlop with a KStep. Everything works perfectly except for this issue.

[TomKerekes]

You are correct they should behave the same and have an absolute minimum high voltage of 2.4V.

Could you have a short between outputs?

You might disconnect everything then test right at KFLOP.

Do all 8 behave the same?

[xuphoenix]

I'm using female jumper wires to connect KFlop, so it's not likely to have a short between the pins.

I disconnected KFlop and KStep and tested IO16-25 and IO26-35 again. They are
IO16-23: 2.99V
IO24-25: 3.27V
IO26-33: 1.74V
IO34-35: 2.49V

The voltage of JP6 is lower than JP4. That's what I got from my KFlop REV 1.3. I use a 12V computer power supply to power the board with the USB jumper removed.

[TomKerekes]

Those results are opposite what was stated originally. Did you make a mistake or did the problem change?

You might try Flashing New Version and re-booting to make sure nothing was changed in KFLOP. Although I can't think of what might cause such a problem.

Are you putting the Outputs high one at a time? You might try one at a time and check what the voltage is and if it affects any others.

You might check or try a different +5V supply. Sometimes PC Power Supplies act strange when supplying low power like what KFLOP draws.

Otherwise it seems you have a damaged KFLOP.

[xuphoenix]

Sorry, I made a mistake in my original description and corrected it in the second one. I tried a different power supply or USB power. Still the same. I think it's broken somehow.

[xuphoenix]

Thank you soooo much, Tom! The problem comes from the J2 jumper. I forgot to check J2. Thank you again.

[TomKerekes]

My apologies I forgot there is Jumper J2 which can change a number of IO pins to operate with a 2.5V supply instead of a 3.3V Supply. Or if not installed basically no supply at all. It should be installed as shown below between pins 1 and 2. I think this is the issue. I see in your email/post this was in fact the issue.