Hi everyone :
I have some questions about nrf51822 ble S110 ,I have two ble device ,both device used S110,is it possible use the first device to scan the second device to get the RSSI value?
To be able to let other device detect and read RSSI one must advertise. To do that you can use S130 that can advertise and scan at the same time. Or you can use S110 and timeslot API so that you can do scanning manually. Here is an example.