From e1b686318fab1cb2b11542c28d82d810d1fc63a2 Mon Sep 17 00:00:00 2001
From: michael-west <michael.west@ettus.com>
Date: Mon, 8 May 2017 11:48:45 -0700
Subject: X300: Fix DAC sync

---
 host/lib/usrp/x300/x300_adc_dac_utils.cpp   | 47 -----------------------------
 host/lib/usrp/x300/x300_radio_ctrl_impl.cpp | 20 ++++++++----
 2 files changed, 14 insertions(+), 53 deletions(-)

diff --git a/host/lib/usrp/x300/x300_adc_dac_utils.cpp b/host/lib/usrp/x300/x300_adc_dac_utils.cpp
index 6fd0ca50b..a6815286e 100644
--- a/host/lib/usrp/x300/x300_adc_dac_utils.cpp
+++ b/host/lib/usrp/x300/x300_adc_dac_utils.cpp
@@ -20,53 +20,6 @@
 
 using namespace uhd::usrp::x300;
 
-/***********************************************************************
- * DAC: Reset and synchronization operations
- **********************************************************************/
-
-void x300_impl::synchronize_dacs(const std::vector<radio_perifs_t*>& radios)
-{
-    if (radios.size() < 2) return;  //Nothing to synchronize
-
-    //**PRECONDITION**
-    //This function assumes that all the VITA times in "radios" are synchronized
-    //to a common reference. Currently, this function is called in get_tx_stream
-    //which also has the same precondition.
-
-    //Reinitialize and resync all DACs
-    for (size_t i = 0; i < radios.size(); i++) {
-        radios[i]->dac->reset();
-    }
-
-    //Get a rough estimate of the cumulative command latency
-    boost::posix_time::ptime t_start = boost::posix_time::microsec_clock::local_time();
-    for (size_t i = 0; i < radios.size(); i++) {
-        radios[i]->ctrl->peek64(uhd::usrp::radio::RB64_TIME_NOW); //Discard value. We are just timing the call
-    }
-    boost::posix_time::time_duration t_elapsed =
-        boost::posix_time::microsec_clock::local_time() - t_start;
-
-    //Add 100% of headroom + uncertaintly to the command time
-    uint64_t t_sync_us = (t_elapsed.total_microseconds() * 2) + 13000 /*Scheduler latency*/;
-
-    //Pick radios[0] as the time reference.
-    uhd::time_spec_t sync_time =
-        radios[0]->time64->get_time_now() + uhd::time_spec_t(((double)t_sync_us)/1e6);
-
-    //Send the sync command
-    for (size_t i = 0; i < radios.size(); i++) {
-        radios[i]->ctrl->set_time(sync_time);
-        radios[i]->ctrl->poke32(uhd::usrp::radio::sr_addr(uhd::usrp::radio::DACSYNC), 0x1);    //Arm FRAMEP/N sync pulse
-        radios[i]->ctrl->set_time(uhd::time_spec_t(0.0));   //Clear command time
-    }
-
-    //Wait and check status
-    boost::this_thread::sleep(boost::posix_time::microseconds(t_sync_us));
-    for (size_t i = 0; i < radios.size(); i++) {
-        radios[i]->dac->verify_sync();
-    }
-}
-
 /***********************************************************************
  * ADC: Self-test operations
  **********************************************************************/
diff --git a/host/lib/usrp/x300/x300_radio_ctrl_impl.cpp b/host/lib/usrp/x300/x300_radio_ctrl_impl.cpp
index 69eb51f55..a3bc2e691 100644
--- a/host/lib/usrp/x300/x300_radio_ctrl_impl.cpp
+++ b/host/lib/usrp/x300/x300_radio_ctrl_impl.cpp
@@ -608,8 +608,14 @@ void x300_radio_ctrl_impl::synchronize_dacs(const std::vector<x300_radio_ctrl_im
     boost::posix_time::time_duration t_elapsed =
         boost::posix_time::microsec_clock::local_time() - t_start;
 
-    //Add 100% of headroom + uncertaintly to the command time
-    uint64_t t_sync_us = (t_elapsed.total_microseconds() * 2) + 13000 /*Scheduler latency*/;
+    //Set tick rate and make sure FRAMEP/N is 0
+    for (size_t i = 0; i < radios.size(); i++) {
+        radios[i]->set_command_tick_rate(radios[i]->_radio_clk_rate, IO_MASTER_RADIO);
+        radios[i]->_regs->misc_outs_reg.write(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 0);
+    }
+
+    //Add 100% of headroom + uncertainty to the command time
+    uint64_t t_sync_us = (t_elapsed.total_microseconds() * 2) + 16000 /*Scheduler latency*/;
 
     //Pick radios[0] as the time reference.
     uhd::time_spec_t sync_time =
@@ -617,15 +623,17 @@ void x300_radio_ctrl_impl::synchronize_dacs(const std::vector<x300_radio_ctrl_im
 
     //Send the sync command
     for (size_t i = 0; i < radios.size(); i++) {
-        radios[i]->set_command_tick_rate(radios[i]->_radio_clk_rate, IO_MASTER_RADIO);
-        radios[i]->_regs->misc_outs_reg.set(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 0);
         radios[i]->set_command_time(sync_time, IO_MASTER_RADIO);
         //Arm FRAMEP/N sync pulse by asserting a rising edge
-        radios[i]->_regs->misc_outs_reg.set(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 1);
-        radios[i]->_regs->misc_outs_reg.set(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 0);
+        radios[i]->_regs->misc_outs_reg.write(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 1);
         radios[i]->set_command_time(uhd::time_spec_t(0.0), IO_MASTER_RADIO);
     }
 
+    //Reset FRAMEP/N to 0
+    for (size_t i = 0; i < radios.size(); i++) {
+        radios[i]->_regs->misc_outs_reg.write(radio_regmap_t::misc_outs_reg_t::DAC_SYNC, 0);
+    }
+
     //Wait and check status
     boost::this_thread::sleep(boost::posix_time::microseconds(t_sync_us));
     for (size_t i = 0; i < radios.size(); i++) {
-- 
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