Merge pull request ARMmbed#1798 from ARMmbed/enhanced_ack_send

MAC Enhanced ACK TX fix:

Author: Juha Heiskanen

source/MAC/IEEE802_15_4/mac_mcps_sap.c

@@ -1737,7 +1737,6 @@ int8_t mcps_generic_ack_build(protocol_interface_rf_mac_setup_s *rf_ptr, const m
     if (rf_ptr->active_pd_data_request) {
         mac_pd_sap_set_phy_tx_time(rf_ptr, 0, false);
     }
-
     return mcps_pd_data_cca_trig(rf_ptr, buffer);
 }
 
@@ -1814,12 +1813,14 @@ static int8_t mcps_pd_data_cca_trig(protocol_interface_rf_mac_setup_s *rf_ptr, m
         bool cca_enabled;
         if (buffer->fcf_dsn.frametype == MAC_FRAME_ACK) {
             cca_enabled = false;
+            rf_ptr->mac_ack_tx_active = true;
         } else {
             cca_enabled = true;
         }
         mac_pd_sap_set_phy_tx_time(rf_ptr, buffer->tx_time, cca_enabled);
         if (mac_plme_cca_req(rf_ptr) != 0) {
             rf_ptr->macTxProcessActive = false;
+            rf_ptr->mac_ack_tx_active = false;
             return -1;
         }
     } else {

source/MAC/IEEE802_15_4/mac_pd_sap.c

@@ -617,8 +617,6 @@ int8_t mac_pd_sap_data_cb(void *identifier, arm_phy_sap_msg_t *message)
                 if (mcps_generic_ack_build(rf_ptr, &fcf_read, pd_data_ind->data_ptr, &ack_payload, time_stamp) !=0) {
                     return -1;
                 }
-
-                rf_ptr->mac_ack_tx_active = true;
             }
         }