https://devzone.nordicsemi.com/f/nordic-q-a/28433/how-to-close-swdHi there, We are developing bluetooth bracelet using 51xx and 52xx Bluetooth chip and the hard hardware part has been done.However, for safety considerations,we need to disable SWD after the program is downloaded. We want to disable SWD by sending aen-USTelligent Community 13Thu, 18 May 2017 08:00:52 GMThttps://devzone.nordicsemi.com/thread/112289?ContentTypeID=1Thu, 18 May 2017 08:00:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a97bb29c-c425-4c35-a58a-341e9ebfaf11endnode<p>You can disable debugger by enabling read-back protection in UICR by writing to <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/uicr.html?cp=2_2_0_13_0_61#register.APPROTECT">APPROTECT</a> register. This can be indeed done from within the FW any time so you can define your way how to trigger it over BLE. Note that this is one-time action, on nRF51 there is similar register but with different name (RBPCONF) and address in UICR space. Also note that due to bug/design limitation this protection isn&#39;t really effective on nRF51 family.</p><div style="clear:both;"></div>