I have tried the source code and I can make it work. You need to add the following items to it.
1. Trigger GAPCentralRole_StartDiscovery when the role is central.
2. Handle GAP_DEVICE_INFO_EVENT and GAP_DEVICE_DISCOVERY_EVENT in simpleBLECentralEventCB.
By the way, there is mistake in my previous post. You do not need to power recycle CC2541 to change role and the switch time is very fast.
