https://devzone.nordicsemi.com/f/nordic-q-a/13553/how-to-add-characteristic-valid-range-descriptorHi In my project I need to add Characteristic Valid Range descriptor and Characteristic Presentation Format descriptor to characteristics. I added Characteristic Presentation Format descriptor the code I used to add is shown below After adding it showingen-USTelligent Community 13Wed, 04 May 2016 14:58:51 GMThttps://devzone.nordicsemi.com/thread/51715?ContentTypeID=1Wed, 04 May 2016 14:58:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4f42f8ff-380f-417d-b40c-fae0b32342fetesc<p>Hi,</p> <p>The Characteristic Presentation format descriptor is one of the characteristic declarations that are given to <code>sd_ble_gatts_characteristic_add()</code> as part of the GATT Characteristic metadata structure (<code>ble_gatts_char_md_t</code>). You should check that the <code>p_char_pf</code> values are according to specification.</p> <p>Less common Characteristic declarations are provided by the use of <code>sd_ble_gatts_descriptor_add()</code>. The descriptor will be added to the most recently added characteristic. You must use the general <code>ble_gatts_attr_t</code> data structure to make the attribute entry for the GATTS table, and format the value field (<code>.p_value</code>) according to the <a href="https://developer.bluetooth.org/gatt/descriptors/Pages/DescriptorViewer.aspx?u=org.bluetooth.descriptor.valid_range.xml">specification for the Characteristic Valid Range descriptor</a>. See the <a href="http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.s130.api.v2.0.0%2Fgroup___b_l_e___g_a_t_t_s___f_u_n_c_t_i_o_n_s.html&amp;cp=2_6_2_1_0_2_4_2_2&amp;anchor=ga0e1478bd565ad99f998671e3baf9847d"><code>sd_ble_gatts_descriptor_add()</code> documentation</a> for further details.</p> <p>Regards, Terje</p><div style="clear:both;"></div>