usrp: added a time sync check for multi usrp

2 files changed, 17 insertions, 0 deletions

diff --git a/host/include/uhd/usrp/multi_usrp.hpp b/host/include/uhd/usrp/multi_usrp.hpp
index 5380d177d..98ba07fc0 100644
--- a/host/include/uhd/usrp/multi_usrp.hpp
+++ b/host/include/uhd/usrp/multi_usrp.hpp
@@ -145,6 +145,14 @@ public:
     virtual void set_time_unknown_pps(const time_spec_t &time_spec) = 0;
 
     /*!
+     * Are the times across all motherboards in this configuration synchronized?
+     * Checks that all time registers are approximately close but not exact,
+     * given that the RTT may varying for a control packet transaction.
+     * \return true when all motherboards time registers are in sync
+     */
+    virtual bool get_time_synchronized(void) = 0;
+
+    /*!
      * Issue a stream command to the usrp device.
      * This tells the usrp to send samples into the host.
      * See the documentation for stream_cmd_t for more info.
diff --git a/host/lib/usrp/multi_usrp.cpp b/host/lib/usrp/multi_usrp.cpp
index 024a6152d..876f1a3fc 100644
--- a/host/lib/usrp/multi_usrp.cpp
+++ b/host/lib/usrp/multi_usrp.cpp
@@ -154,6 +154,15 @@ public:
         }
     }
 
+    bool get_time_synchronized(void){
+        for (size_t m = 1; m < get_num_mboards(); m++){
+            time_spec_t time_0 = _mboard(0)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+            time_spec_t time_i = _mboard(m)[MBOARD_PROP_TIME_NOW].as<time_spec_t>();
+            if (time_i < time_0 or (time_i - time_0) > time_spec_t(0.01)) return false;
+        }
+        return true;
+    }
+
     void issue_stream_cmd(const stream_cmd_t &stream_cmd){
         for (size_t m = 0; m < get_num_mboards(); m++){
             _mboard(m)[MBOARD_PROP_STREAM_CMD] = stream_cmd;