https://devzone.nordicsemi.com/f/nordic-q-a/12852/ptr5518-io-pinsHi I&#39;m very new and looking at the PTR5518 breakout board. The docs below specify some of the pins: Are the pins EN , RX , TX , RTS etc. tied to P0.08, P0.09, P0.12, P0.19, respectively, only in the stock firmware? That is, these pins areen-USTelligent Community 13Wed, 30 Mar 2016 10:52:42 GMThttps://devzone.nordicsemi.com/thread/48876?ContentTypeID=1Wed, 30 Mar 2016 10:52:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:80749a7e-6b8e-4d56-bce2-98c28a48bbb7Ole Bauck<p>Hi</p> <p>You can use SWDIO and SWDCLK for programming so no need to worry about the RTS and EN pins. Normally RTS and CTS is UART flowcontrol pins, but in this case I am not sure since the module has a separate FLOW_CTR pin. Does the datasheet say anything about what the RTS and CTS pins are used for?</p> <p>From my understanding EN is equal to NO1 which is equal to P0.08. All digital functions on the nRF51 can be assigned to any pin, only analog functions (ADC, LPCOMP) needs specific pins (AIN0-AIN7).</p><div style="clear:both;"></div>