https://devzone.nordicsemi.com/f/nordic-q-a/13166/is-any-additional-settings-needed-be-configures-for-gpio9-and-10Hi all: Based the descriptions in data sheet, the GPIO9 and 10 are set to NFC antenna pins by default. And I cannot control these 2 pin correctly by configuring the pins as below NRF_GPIO-&gt;PIN_CNF[OLED_RESET_PIN_NUMBER] = (GPIO_PIN_CNF_DIR_Outputen-USTelligent Community 13Thu, 21 Apr 2016 14:42:45 GMThttps://devzone.nordicsemi.com/thread/50201?ContentTypeID=1Thu, 21 Apr 2016 14:42:45 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a812cfd0-b477-42f8-ba67-0538ba8a53e0Jorgewu<p>Please use the API of NVMC to write it..</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/50203?ContentTypeID=1Thu, 21 Apr 2016 06:41:13 GMT137ad170-7792-4731-bb38-c0d22fbe4515:079c5a5f-2786-487f-87f3-1c2925bace71jixing.zou<p>See this <a href="https://devzone.nordicsemi.com/question/55696/struggling-with-basic-gpio-read-on-nrf52/">link text</a></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/50202?ContentTypeID=1Wed, 13 Apr 2016 03:57:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b03160c2-f319-45b5-8011-74fe81c8e7deWojtek<p>Yes, you should clear NFCPINS register in UICR. (value 0 means that pins works as gpio, but by default this register contains 0xFFFFFFFF which means that pins are used as NFC antenna).</p> <p>I think you should use NVMC to write to UICR...</p><div style="clear:both;"></div>