--- a/master/master.c	Mon Jan 09 17:42:12 2012 +0100
+++ b/master/master.c	Mon Jan 09 17:42:28 2012 +0100
@@ -1236,7 +1236,9 @@
     ec_master_t *master = (ec_master_t *) priv_data;
     ec_slave_t *slave = NULL;
     int fsm_exec;
+#ifdef EC_USE_HRTIMER
     size_t sent_bytes;
+#endif
 
     // send interval in IDLE phase
     ec_master_set_send_interval(master, 1000000 / HZ); 
@@ -1271,8 +1273,10 @@
             ec_master_queue_datagram(master, &master->fsm_datagram);
         }
         ecrt_master_send(master);
+#ifdef EC_USE_HRTIMER
         sent_bytes = master->main_device.tx_skb[
             master->main_device.tx_ring_index]->len;
+#endif
         up(&master->io_sem);
 
         if (ec_fsm_master_idle(&master->fsm)) {