Add no audio agc

nanovna.h

@@ -880,6 +880,7 @@ typedef struct config {
 #endif
 #ifdef TINYSA4
   uint8_t hide_21MHz;
+  uint8_t no_audio_agc;
 #endif
   float sweep_voltage;
   float switch_offset;

sa_core.c

@@ -4446,11 +4446,11 @@ again:                                                              // Spur redu
 #endif
             else if (get_sweep_frequency(ST_SPAN)<50000000 || max2871) { // When scanning less then 50MHz
               if (actual_rbw_x10 <= 3000) {
-                freq_t shift = (max2871 ? 700000 : 0);
+                freq_t shift = (max2871 ? 0 : 0);
                 freq_t tf= ((lf - shift + actual_rbw_x10*1000) / TXCO_DIV3) * TXCO_DIV3;
                 if (tf + shift + actual_rbw_x10*1000 >= lf  && tf + shift < lf + actual_rbw_x10*1000) // 10MHz
                   if (max2871)
-                    ADF4351_R_counter(3);    // To avoid PLL Loop shoulders at multiple of 10MHz
+                    ADF4351_R_counter(1);
                   else
                     ADF4351_R_counter(-4);    // To avoid PLL Loop shoulders at multiple of 10MHz
                 else {

si4468.c

@@ -2136,6 +2136,9 @@ void SI4432_Listen(int s)
 //  SI4463_WAIT_CTS;                // Wait for CTS
   do {
       uint8_t v = Si446x_readRSSI();
+      if (config.no_audio_agc) {
+        DAC->DHR12R1 = v << 4; // Use DAC: CH1 and put 12 bit right aligned value
+      } else {
         if (max < v)                // Peak
           max = v;
         if (count > 1000) {         // Decay
@@ -2145,6 +2148,7 @@ void SI4432_Listen(int s)
           count++;
         v = max - v;
         DAC->DHR12R1 = dBm_to_volt[v] << 4; // Use DAC: CH1 and put 12 bit right aligned value
+      }
     } while(operation_requested == OP_NONE);
   count = 0;
 //  dacPutChannelX(&DACD2, 0, 0);

ui.c

@@ -2782,6 +2782,21 @@ static UI_FUNCTION_ADV_CALLBACK(menu_linear_averaging_acb)
   ui_mode_normal();
 }
 
+static UI_FUNCTION_ADV_CALLBACK(menu_audio_agc_acb)
+{
+  (void)data;
+  (void)item;
+  if (b){
+    b->icon = config.no_audio_agc ? BUTTON_ICON_NOCHECK : BUTTON_ICON_CHECK;
+    return;
+  }
+  config.no_audio_agc = ! config.no_audio_agc;
+  dirty = true;
+  config_save();
+  //  menu_move_back();
+  ui_mode_normal();
+}
+
 
 #endif
 
@@ -4941,6 +4956,7 @@ static const menuitem_t menu_settings[] =
   { MT_ADV_CALLBACK,0,              "PROGRESS\nBAR",        menu_progress_bar_acb},
   { MT_ADV_CALLBACK,     0,         "DIRECT\nMODE",         menu_direct_acb},
   { MT_ADV_CALLBACK,     0,         "LINEAR\nAVERAGING",    menu_linear_averaging_acb},
+  { MT_ADV_CALLBACK,     0,         "AUDIO\nAGC",           menu_audio_agc_acb},
 #ifdef __HARMONIC__
   { MT_SUBMENU          ,0,         "HARMONIC",             menu_harmonic},
 #endif