High overshoot in UART signal

[ndc_bee]

Hi Nordic

In our product, nRF52832 is connected with another MCU through UART. We find that the overshoot in UART signal is very high.

The yellow one is the TX signal. The highest voltage is about 4V. Test point is at the pin of nRF52832.

The UART interface uses GPIO P0.05 to P0.08.

We want to ask that does this overshoot damage the nRF52832 chip?

[hmolesworth]

The probe is unbalanced (not correctly compensated to match the instrument); look for the tiny screw adjuster on the probe and slightly rotate with a screwdriver to bring the trace flat rather than curved which will also reduce the displayed (apparent) overshoot. Also ensure the 'scope probe Gnd connection to 0V is used for cleanest display.

[ndc_bee]

Thank you for your answer.

We have calibrate the prob before the test and use a short GND path.

So I think this may not be the main reason for this situation.

[hmolesworth]

Looks like you are using x1 probe setting; try instead using x10 setting (10MOhm impedance). The traces still don't look correctly matched to the instrument - they should be perfectly flat outside the transitions.