https://devzone.nordicsemi.com/f/nordic-q-a/16062/double-direction-communication-problem-in-esb-protocol-ptx----prx----ptxHey, I have two nrf52 development board. One is PRX, one is PTX. I try to realize the scenario that: PTX transmits a number like &quot;100&quot;, PRX receives this data &quot;100&quot; and plus &quot;1&quot;. Now data is &quot;101&quot; at the PRX side. And PRX transmits &quot;101&quot; to PTX asen-USTelligent Community 13Wed, 31 Aug 2016 07:28:39 GMThttps://devzone.nordicsemi.com/thread/61251?ContentTypeID=1Wed, 31 Aug 2016 07:28:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8b35db16-565a-4b27-bb2b-cbcccefd8db8Einar Thorsrud<p>The initial case you describe seems OK to me (unless I got something wrong):</p> <ol> <li>PTX sends a number (100) to the PRX</li> <li>PRX adds 1 to the received number and sends that number (101) in the ACK <em>with payload</em>.</li> </ol> <p>To implement this the PRX should use selective ack and use <code>nrf_esb_write_payload()</code> to write the data that goes in the ack package.</p> <p>Regarding the updated part of your question. Why do you have to switch mode, if you only need to send a ack with payload? Can you be more specific about what you do in this case, and what happens before the chip is reset? It could be due to an APP_ERROR_CHECK that fails, and if so, it can easily be debugged (described in <a href="https://devzone.nordicsemi.com/blogs/821">An introduction to error handling in nRF5 projects</a>).</p><div style="clear:both;"></div>