IAR Compiler error Undefined external GAP_DeviceDiscoveryRequest relay TI CC2540
Undefined external "GAP_DeviceDiscoveryRequest::?relay" error occurs when you attempt to extend your observer code or peripheral code to be peripheral AND observer.
If this is the case, remove your current LIB reference (expand the project tree) and add the lib CC2540_ BLE_peri_observ.lib which can be found in BLE-CC254x-1.3.2\Projects\ble\Libraries\CC2540DB\bin
See also