https://devzone.nordicsemi.com/f/nordic-q-a/4521/bliny-project-in-nrf6310Hi, In the step 3 of the &quot;nRF51822_Development_Kit_User_Guide_v1.4&quot; (page 11) : Select nRF51822 from the Select Target list and click Build or press F7 to compile the Blinky project. I see various targets to select: nrf51822_xxaa (256ken-USTelligent Community 13Thu, 20 Nov 2014 10:23:24 GMThttps://devzone.nordicsemi.com/thread/16038?ContentTypeID=1Thu, 20 Nov 2014 10:23:24 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c489b3aa-d733-40bc-a44c-0aad64312f2fStian R&#248;ed Hafskjold<p>Philip is right. There are two different chip versions, one with 256k flash (xxaa) and one with 128k (xxab). The chip version is written on the chip. The other options with s110 and s120 are when you use one of the the softdevices, for the application memory addresses to be set correctly.</p> <p>The blinky project does not use a SoftDevice, and if you are using the dev kit you have the qfaa chip. Hence, <code>nrf51822_xxaa (256k)</code> is the correct one.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/16039?ContentTypeID=1Thu, 20 Nov 2014 00:37:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2a467218-e9ad-4d8e-86ab-ae2a4abc07bbPhilip Freidin<p>You should choose the first entry: nrf51822_xxaa (256k)</p> <p>This matches the device on the boards you have, which are probably nRF51822_QFAA_C0.</p> <p>The entries with S110 or S120 are for designs using the Bluetooth Low Energy SoftDevices,</p> <p>and the 3 entries with (128k) are for devices with less flash memory, which are all &quot;ab&quot; parts (you have 2 misprints) .</p><div style="clear:both;"></div>