diff --git a/source/NanostackRfPhyAtmel.cpp b/source/NanostackRfPhyAtmel.cpp
index 8d60cc3..a62e1fe 100644
--- a/source/NanostackRfPhyAtmel.cpp
+++ b/source/NanostackRfPhyAtmel.cpp
@@ -26,6 +26,7 @@
 #include "nanostack/platform/arm_hal_phy.h"
 #include "mbed_trace.h"
 #include "mbed_toolchain.h"
+#include "events/mbed_shared_queues.h"
 
 #define TRACE_GROUP "AtRF"
 
@@ -219,17 +220,8 @@ static inline rf_trx_states_t rf_if_trx_status_from_full(uint8_t full_trx_status
 
 #ifdef MBED_CONF_RTOS_PRESENT
 #include "mbed.h"
-#include "rtos.h"
 
 static void rf_if_irq_task_process_irq();
-
-#define SIG_RADIO       1
-#define SIG_TIMER_ACK   2
-#define SIG_TIMER_CAL   4
-#define SIG_TIMER_CCA   8
-
-#define SIG_TIMERS (SIG_TIMER_ACK|SIG_TIMER_CAL|SIG_TIMER_CCA)
-#define SIG_ALL (SIG_RADIO|SIG_TIMERS)
 #endif
 
 // HW pins to RF chip
@@ -256,9 +248,7 @@ class RFBits {
     Timeout cal_timer;
     Timeout cca_timer;
 #ifdef MBED_CONF_RTOS_PRESENT
-    Thread irq_thread;
-    Mutex mutex;
-    void rf_if_irq_task();
+    EventQueue *equeue;
 #endif
 };
 
@@ -270,12 +260,9 @@ RFBits::RFBits(PinName spi_mosi, PinName spi_miso,
         RST(spi_rst),
         SLP_TR(spi_slp),
         IRQ(spi_irq)
-#ifdef MBED_CONF_RTOS_PRESENT
-,irq_thread(osPriorityRealtime, 1024)
-#endif
 {
 #ifdef MBED_CONF_RTOS_PRESENT
-    irq_thread.start(mbed::callback(this, &RFBits::rf_if_irq_task));
+    equeue = mbed_highprio_event_queue();
 #endif
 }
 
@@ -284,6 +271,9 @@ static uint8_t rf_part_num = 0;
 /*TODO: RSSI Base value setting*/
 static int8_t rf_rssi_base_val = -91;
 
+/* Lock against background operations (disable interrupts, or claim the
+ * background mutex).
+ */
 static void rf_if_lock(void)
 {
     platform_enter_critical();
@@ -294,20 +284,37 @@ static void rf_if_unlock(void)
     platform_exit_critical();
 }
 
+/* Perform lock from a background operation (nothing, if background are
+ * interrupts, else claim the background mutex)
+ */
+static void rf_if_lock_in_bg(void)
+{
+#ifdef MBED_CONF_RTOS_PRESENT
+    rf_if_lock();
+#endif
+}
+
+static void rf_if_unlock_in_bg(void)
+{
+#ifdef MBED_CONF_RTOS_PRESENT
+    rf_if_unlock();
+#endif
+}
+
 #ifdef MBED_CONF_RTOS_PRESENT
 static void rf_if_cca_timer_signal(void)
 {
-    rf->irq_thread.signal_set(SIG_TIMER_CCA);
+    rf->equeue->call(rf_cca_timer_interrupt);
 }
 
 static void rf_if_cal_timer_signal(void)
 {
-    rf->irq_thread.signal_set(SIG_TIMER_CAL);
+    rf->equeue->call(rf_calibration_timer_interrupt);
 }
 
 static void rf_if_ack_timer_signal(void)
 {
-    rf->irq_thread.signal_set(SIG_TIMER_ACK);
+    rf->equeue->call(rf_ack_wait_timer_interrupt);
 }
 #endif
 
@@ -1033,33 +1040,7 @@ static void rf_if_disable_irq(void)
 #ifdef MBED_CONF_RTOS_PRESENT
 static void rf_if_interrupt_handler(void)
 {
-    rf->irq_thread.signal_set(SIG_RADIO);
-}
-
-// Started during construction of rf, so variable
-// rf isn't set at the start. Uses 'this' instead.
-void RFBits::rf_if_irq_task(void)
-{
-    for (;;) {
-        osEvent event = irq_thread.signal_wait(0);
-        if (event.status != osEventSignal) {
-            continue;
-        }
-        rf_if_lock();
-        if (event.value.signals & SIG_RADIO) {
-            rf_if_irq_task_process_irq();
-        }
-        if (event.value.signals & SIG_TIMER_ACK) {
-            rf_ack_wait_timer_interrupt();
-        }
-        if (event.value.signals & SIG_TIMER_CCA) {
-            rf_cca_timer_interrupt();
-        }
-        if (event.value.signals & SIG_TIMER_CAL) {
-            rf_calibration_timer_interrupt();
-        }
-        rf_if_unlock();
-    }
+    rf->equeue->call(rf_if_irq_task_process_irq);
 }
 
 static void rf_if_irq_task_process_irq(void)
@@ -1074,6 +1055,8 @@ static void rf_if_irq_task_process_irq(void)
 static void rf_if_interrupt_handler(void)
 #endif
 {
+  rf_if_lock_in_bg();
+
   static uint8_t last_is, last_ts;
   uint8_t irq_status, full_trx_status;
   uint8_t orig_xah_ctrl_1 = xah_ctrl_1;
@@ -1107,6 +1090,8 @@ static void rf_if_interrupt_handler(void)
   }
   last_is = irq_status;
   last_ts = full_trx_status;
+
+  rf_if_unlock_in_bg();
 }
 
 /*
@@ -1278,10 +1263,14 @@ static void rf_ack_wait_timer_interrupt(void)
  */
 static void rf_calibration_timer_interrupt(void)
 {
+    rf_if_lock_in_bg();
+
     /*Calibrate RF*/
     rf_calibration_cb();
     /*Start new calibration timeout*/
     rf_calibration_timer_start(RF_CALIBRATION_INTERVAL);
+
+    rf_if_unlock_in_bg();
 }
 
 /*
@@ -1293,9 +1282,13 @@ static void rf_calibration_timer_interrupt(void)
  */
 static void rf_cca_timer_interrupt(void)
 {
+    rf_if_lock_in_bg();
+
     rf_flags_set(RFF_CCA);
     /*Start CCA process*/
     rf_if_start_cca_process();
+
+    rf_if_unlock_in_bg();
 }
 
 /*