HCI_ISO_TX_SDU_ARRIVAL_MARGIN_US

#define HCI_ISO_TX_SDU_ARRIVAL_MARGIN_US   1000

#include <softdevice_controller/include/sdc_hci.h>

The arrival margin in microseconds the controller needs to receive an ISO SDU before it can be sent on air.

For more details, see the SoftDevice Controller documentation that describes how to provide data for isochronous channels.