From 59aaf137b8c86028c0686258837acc7f37eb9461 Mon Sep 17 00:00:00 2001
From: Derek Kozel <derek.kozel@ettus.com>
Date: Tue, 25 Oct 2016 17:26:25 -0700
Subject: TwinRX: Use command time to schedule synchronous events

---
 host/lib/usrp/dboard/twinrx/twinrx_experts.cpp | 24 ++++++++++++++++
 host/lib/usrp/dboard/twinrx/twinrx_experts.hpp | 39 ++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

(limited to 'host/lib/usrp/dboard/twinrx')

diff --git a/host/lib/usrp/dboard/twinrx/twinrx_experts.cpp b/host/lib/usrp/dboard/twinrx/twinrx_experts.cpp
index ddaa4211e..f0f64c7e1 100644
--- a/host/lib/usrp/dboard/twinrx/twinrx_experts.cpp
+++ b/host/lib/usrp/dboard/twinrx/twinrx_experts.cpp
@@ -29,6 +29,17 @@ using namespace uhd::experts;
 using namespace uhd::math;
 using namespace uhd::usrp::dboard::twinrx;
 
+/*!---------------------------------------------------------
+ * twinrx_scheduling_expert::resolve
+ * ---------------------------------------------------------
+ */
+void twinrx_scheduling_expert::resolve()
+{
+    // Currently a straight pass-through. To be expanded as needed
+    // when more advanced scheduling is needed
+    _rx_frontend_time = _command_time;
+}
+
 /*!---------------------------------------------------------
  * twinrx_freq_path_expert::resolve
  * ---------------------------------------------------------
@@ -222,6 +233,19 @@ void twinrx_freq_coercion_expert::resolve()
  */
 void twinrx_nyquist_expert::resolve()
 {
+    // Do not execute when clear_command_time is called.
+    // This is a transition of the command time from non-zero to zero.
+    if (_rx_frontend_time == time_spec_t(0.0) and _cached_cmd_time != time_spec_t(0.0)) {
+        _cached_cmd_time = _rx_frontend_time;
+        return;
+    }
+
+    // Do not execute twice for the same command time unless untimed
+    if (_rx_frontend_time == _cached_cmd_time and _rx_frontend_time != time_spec_t(0.0)) {
+        return;
+    }
+    _cached_cmd_time = _rx_frontend_time;
+
     double if_freq_sign = 1.0;
     if (_lo1_inj_side == INJ_HIGH_SIDE) if_freq_sign *= -1.0;
     if (_lo2_inj_side == INJ_HIGH_SIDE) if_freq_sign *= -1.0;
diff --git a/host/lib/usrp/dboard/twinrx/twinrx_experts.hpp b/host/lib/usrp/dboard/twinrx/twinrx_experts.hpp
index 1617c9c80..9c83dbfa8 100644
--- a/host/lib/usrp/dboard/twinrx/twinrx_experts.hpp
+++ b/host/lib/usrp/dboard/twinrx/twinrx_experts.hpp
@@ -52,6 +52,38 @@ static const std::string lo_stage_str(lo_stage_t stage, bool lower = false) {
     return prefix + ((stage == STAGE_LO1) ? "1" : "2");
 }
 
+
+/*!---------------------------------------------------------
+ * twinrx_scheduling_expert
+ *
+ * This expert is responsible for scheduling time sensitive actions
+ * in other experts. It responds to changes in the command time and
+ * selectively causes experts to run in order to ensure a synchronized
+ * system.
+ *
+ * ---------------------------------------------------------
+ */
+class twinrx_scheduling_expert : public experts::worker_node_t {
+public:
+    twinrx_scheduling_expert(const experts::node_retriever_t& db, std::string ch)
+    : experts::worker_node_t(prepend_ch("twinrx_scheduling_expert", ch)),
+      _command_time     (db, prepend_ch("time/cmd", ch)),
+      _rx_frontend_time (db, prepend_ch("time/rx_frontend", ch))
+    {
+        bind_accessor(_command_time);
+        bind_accessor(_rx_frontend_time);
+    }
+
+private:
+    virtual void resolve();
+
+    //Inputs
+    experts::data_reader_t<time_spec_t>    _command_time;
+
+    //Outputs
+    experts::data_writer_t<time_spec_t>    _rx_frontend_time;
+};
+
 /*!---------------------------------------------------------
  * twinrx_freq_path_expert
  *
@@ -271,6 +303,7 @@ public:
       _if_freq_d        (db, prepend_ch("if_freq/desired", ch)),
       _lo1_inj_side     (db, prepend_ch("ch/LO1/inj_side", ch)),
       _lo2_inj_side     (db, prepend_ch("ch/LO2/inj_side", ch)),
+      _rx_frontend_time (db, prepend_ch("time/rx_frontend", ch)),
       _if_freq_c        (db, prepend_ch("if_freq/coerced", ch)),
       _db_iface         (db_iface)
     {
@@ -280,6 +313,7 @@ public:
         bind_accessor(_lo1_inj_side);
         bind_accessor(_lo2_inj_side);
         bind_accessor(_if_freq_c);
+        bind_accessor(_rx_frontend_time);
     }
 
 private:
@@ -293,9 +327,14 @@ private:
     experts::data_reader_t<double>                          _if_freq_d;
     experts::data_reader_t<lo_inj_side_t>                   _lo1_inj_side;
     experts::data_reader_t<lo_inj_side_t>                   _lo2_inj_side;
+    experts::data_reader_t<time_spec_t>                     _rx_frontend_time;
+
     //Outputs
     experts::data_writer_t<double>                          _if_freq_c;
     dboard_iface::sptr                                      _db_iface;
+
+    //Misc
+    time_spec_t  _cached_cmd_time;
 };
 
 /*!---------------------------------------------------------
-- 
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