nRF8001 - RDYN pin not going HIGH after readout

Question

Hey, 
 I am using a nRF8001 with a STM32L051 as an application controller. 
 After resetting the nRF the RDYN pin goes low, as expected. Then I'm setting the REQN line LOW and read out the DeviceStartedEvent. After putting the REQN line back HIGH, the RDYN pin stays low, so I can't communicate further with the nRF. 
 Do you have a clue what could get wrong? 
 Thanks 
 Paul

David Edwin · Answer

If the RDYN line is low, that means data is available in the nRF8001 and should be clocked out. Continue to clock out the ACI so all the data is clocked out. After each ACI message is clocked out you must set the REQN high. Look at s ection 7 in the nRF8001 Product specifications for details on handling the ACI lines. Example code for handling the ACI interface is present in ble-sdk-arduino project . The https://github.com/NordicSemiconductor/ble-sdk-arduino/tree/master/documentation/libraries/BLE (library architecture document) explains more about handling the ACI interrface.