https://devzone.nordicsemi.com/f/nordic-q-a/114162/nrf52840-uart-ex---new-chip-revision-uart-handling-changed-somehowHello we have some own created UART drivers which access the UART registers directly. Those drivers have been working withe the older chip revisions for years. Currently we are going to the &quot;newer&quot; chip revisions and observe that those drivers noen-USTelligent Community 13Fri, 23 Aug 2024 13:53:28 GMThttps://devzone.nordicsemi.com/thread/499591?ContentTypeID=1Fri, 23 Aug 2024 13:53:28 GMT137ad170-7792-4731-bb38-c0d22fbe4515:765deb7a-12d0-48a0-8271-faa480c1bad1rgrr2<p>okay, sorry for the noise.&nbsp; Found the problem: cause is, that the setup of the RTS/CTS were wrong all the time if there is no hardware handshake.&nbsp; Set both registers to 0xffffffff solved the problem.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/499585?ContentTypeID=1Fri, 23 Aug 2024 13:29:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fdb0e5e8-1517-4eac-8f31-0eb5c35dd68brgrr2<p>Hardware is PCA10056, old DK 2.x and new DK 3.x</p><div style="clear:both;"></div>