From 225464c51af8ddf28951ee6bb105df8621a6f5d6 Mon Sep 17 00:00:00 2001
From: Reed Nightingale <reed.nightingale@gmail.com>
Date: Sun, 2 Feb 2020 15:19:44 -0800
Subject: [PATCH] Remove TX offset in CW mode, and refactor frequency setting
 code so that it's (almost) all in one place. W0EB pointed out this issue, and
 it appears that it was discussed but never implemented in
 https://groups.io/g/BITX20/topic/20916360

---
 setup.cpp   |  1 -
 ubitx.h     |  2 +-
 ubitxv6.ino | 71 ++++++++++++++++++++++++++---------------------------
 3 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/setup.cpp b/setup.cpp
index 70852ff..89f7c04 100644
--- a/setup.cpp
+++ b/setup.cpp
@@ -147,7 +147,6 @@ void ssLocalOscInitialize(long int* start_value_out){
     uint32_t freq = GetActiveVfoFreq();
     freq = (freq/1000L) * 1000L;//round off the current frequency the nearest kHz
     setFrequency(freq);
-    si5351bx_setfreq(0, globalSettings.usbCarrierFreq); //set back the carrier oscillator, cw tx switches it off
   }
   *start_value_out = globalSettings.oscillatorCal;
 }
diff --git a/ubitx.h b/ubitx.h
index 0800e75..3218d9f 100644
--- a/ubitx.h
+++ b/ubitx.h
@@ -95,7 +95,7 @@ static const uint32_t THRESHOLD_USB_LSB = 10000000L;
 /* these are functions implemented in the main file named as ubitx_xxx.ino */
 void active_delay(int delay_by);
 void saveVFOs();
-void setFrequency(unsigned long f);
+void setFrequency(const unsigned long freq, const bool transmit = false);
 void startTx(TuningMode_e tx_mode);
 void stopTx();
 void ritEnable(unsigned long f);
diff --git a/ubitxv6.ino b/ubitxv6.ino
index 0efc991..44437e1 100644
--- a/ubitxv6.ino
+++ b/ubitxv6.ino
@@ -155,29 +155,48 @@ void setTXFilters_v5(unsigned long freq){
  * through mixing of the second local oscillator.
  */
  
-void setFrequency(unsigned long freq){
-  static const unsigned long firstIF = 45005000L;
+void setFrequency(const unsigned long freq,
+                  const bool transmit){
+  static const unsigned long FIRST_IF = 45005000UL;
  
   setTXFilters(freq);
 
-  uint32_t local_osc_freq;
-  if(TuningMode_e::TUNE_CW == globalSettings.tuningMode){
-    local_osc_freq = firstIF + freq + globalSettings.cwSideToneFreq;
-  }
-  else{
-    local_osc_freq = firstIF + freq;
-  }
+  //Nominal values for the oscillators
+  uint32_t local_osc_freq = FIRST_IF + freq;
+  uint32_t ssb_osc_freq = FIRST_IF;//will be changed depending on sideband
+  uint32_t bfo_osc_freq = globalSettings.usbCarrierFreq;
 
-  uint32_t ssb_osc_freq;
-  if(VfoMode_e::VFO_MODE_USB == GetActiveVfoMode()){
-    ssb_osc_freq = firstIF + globalSettings.usbCarrierFreq;
+  if(TuningMode_e::TUNE_CW == globalSettings.tuningMode){
+    if(transmit){
+      //We don't do any mixing or converting when transmitting
+      local_osc_freq = freq;
+      ssb_osc_freq = 0;
+      bfo_osc_freq = 0;
+    }
+    else{
+      //We offset when receiving CW so that it's audible
+      if(VfoMode_e::VFO_MODE_USB == GetActiveVfoMode()){
+        local_osc_freq -= globalSettings.cwSideToneFreq;
+        ssb_osc_freq += globalSettings.usbCarrierFreq;
+      }
+      else{
+        local_osc_freq += globalSettings.cwSideToneFreq;
+        ssb_osc_freq -= globalSettings.usbCarrierFreq;
+      }
+    }
   }
-  else{
-    ssb_osc_freq = firstIF - globalSettings.usbCarrierFreq;
+  else{//SSB mode
+    if(VfoMode_e::VFO_MODE_USB == GetActiveVfoMode()){
+      ssb_osc_freq += globalSettings.usbCarrierFreq;
+    }
+    else{
+      ssb_osc_freq -= globalSettings.usbCarrierFreq;
+    }
   }
 
   si5351bx_setfreq(2, local_osc_freq);
   si5351bx_setfreq(1, ssb_osc_freq);
+  si5351bx_setfreq(0, bfo_osc_freq);
 
   SetActiveVfoFreq(freq);
 }
@@ -196,7 +215,7 @@ void startTx(TuningMode_e tx_mode){
     //save the current as the rx frequency
     uint32_t rit_tx_freq = globalSettings.ritFrequency;
     globalSettings.ritFrequency = GetActiveVfoFreq();
-    setFrequency(rit_tx_freq);
+    setFrequency(rit_tx_freq,true);
   }
   else{
     if(globalSettings.splitOn){
@@ -207,26 +226,9 @@ void startTx(TuningMode_e tx_mode){
         globalSettings.activeVfo = Vfo_e::VFO_B;
       }
     }
-    setFrequency(GetActiveVfoFreq());
+    setFrequency(GetActiveVfoFreq(),true);
   }
 
-  if(TuningMode_e::TUNE_CW == globalSettings.tuningMode){
-    //turn off the second local oscillator and the bfo
-    si5351bx_setfreq(0, 0);
-    si5351bx_setfreq(1, 0);
-
-    //shift the first oscillator to the tx frequency directly
-    //the key up and key down will toggle the carrier unbalancing
-    //the exact cw frequency is the tuned frequency + sidetone
-    if(VfoMode_e::VFO_MODE_USB == GetActiveVfoMode()){
-      si5351bx_setfreq(2, GetActiveVfoFreq() + globalSettings.cwSideToneFreq);
-    }
-    else{
-      si5351bx_setfreq(2, GetActiveVfoFreq() - globalSettings.cwSideToneFreq);
-    }
-
-    delay(20);
-  }
   digitalWrite(TX_RX, 1);//turn on the tx
   globalSettings.txActive = true;
   drawTx();
@@ -236,9 +238,6 @@ void stopTx(){
   digitalWrite(TX_RX, 0);//turn off the tx
   globalSettings.txActive = false;
 
-  //set back the carrier oscillator - cw tx switches it off
-  si5351bx_setfreq(0, globalSettings.usbCarrierFreq);
-
   if(globalSettings.ritOn){
     uint32_t rit_rx_freq = globalSettings.ritFrequency;
     globalSettings.ritFrequency = GetActiveVfoFreq();