New squelch behavior and fixes

Squelch value now goes from -90 to +20 and it's directly compared against the max_db parameter returned from each freq scanned by the radio subsystem, with no adjusts or manipulation (you adjust the number as will be used).

Less squelch means weaker signals will trigger it. (as expected).

There was a tiny cosmetic bug when you deleted a frequency from the scanning memory: The description was not erased from screen and you could see it while the scan did not resume.

There was another bug on the pause button: If you asked for another manual scan range when paused, the button kept the text "RESUME"  (its text was not reset to "PAUSE" again).

firmware/application/apps/ui_scanner.cpp

@@ -105,7 +105,6 @@ void ScannerThread::run() {
 				EventDispatcher::send_message(message);
 			} 
 			else {									//NOT scanning 									
-				restart_scan=true;					//Flag the need for skipping a cycle when restarting scan
 				if (_freq_del != 0) {				//There is a frequency to delete
 					for (uint16_t i = 0; i < frequency_list_.size(); i++) {	//Search for the freq to delete
 						if (frequency_list_[i] == _freq_del) 
@@ -120,6 +119,9 @@ void ScannerThread::run() {
 					}
 					_freq_del = 0;					//deleted.
 				}
+				else {
+					restart_scan=true;					//Flag the need for skipping a cycle when restarting scan
+				}
 			}
 			chThdSleepMilliseconds(50);				//Needed to (eventually) stabilize the receiver into new freq
 		}
@@ -161,8 +163,10 @@ void ScannerView::show_max() {		//show total number of freqs to scan
 		text_max.set_style(&style_red);
 		text_max.set( "/ " + to_string_dec_uint(MAX_DB_ENTRY) + " (DB MAX!)");
 	}
-	else
+	else {
+		text_max.set_style(&style_grey);
 		text_max.set( "/ " + to_string_dec_uint(frequency_list.size()));
+	}
 }
 
 ScannerView::ScannerView(
@@ -200,8 +204,6 @@ ScannerView::ScannerView(
 	def_step = change_mode(AM);	//Start on AM
 	field_mode.set_by_value(AM);	//Reflect the mode into the manual selector
 
-	//big_display.set_style(&style_grey);	//Start with gray color
-
 	//HELPER: Pre-setting a manual range, based on stored frequency
 	rf::Frequency stored_freq = persistent_memory::tuned_frequency();
 	frequency_range.min = stored_freq - 1000000;
@@ -255,8 +257,7 @@ ScannerView::ScannerView(
 			description_list.erase(description_list.begin() + current_index);
 			frequency_list.erase(frequency_list.begin() + current_index);
 			show_max();								//UPDATE new list size on screen
-			chThdSleepMilliseconds(300);			//"debouncing" pause so user take finger off 
+			desc_cycle.set(" ");					//Clean up description (cosmetic detail)
-			timer = wait * 10;						//Unlock timer pause on_statistics_update
 			scan_thread->set_freq_lock(0); 			//Reset the scanner lock
 			if ( userpause ) 						//If user-paused, resume
 				user_resume();
@@ -296,16 +297,12 @@ ScannerView::ScannerView(
 	};
 
 	field_mode.on_change = [this](size_t, OptionsField::value_t v) {
-		if (scan_thread->is_scanning())
-			scan_thread->set_scanning(false); 	//STOP SCANNING
-		audio::output::stop();
-		scan_thread->stop();
 		receiver_model.disable();
 		baseband::shutdown();
 		change_mode(v);
-		if ( userpause ) 						//If user-paused, resume
+		if ( !scan_thread->is_scanning() ) 						//for some motive, audio output gets stopped.
-			user_resume();
+			audio::output::start();								//So if scan was stopped we resume audio
-		start_scan_thread();
+		receiver_model.enable(); 
 	};
 
 	button_dir.on_select = [this](Button&) {
@@ -357,7 +354,7 @@ ScannerView::ScannerView(
 
 	//PRE-CONFIGURATION:
 	field_wait.on_change = [this](int32_t v) {	wait = v;	}; 	field_wait.set_value(5);
-	field_squelch.on_change = [this](int32_t v) {	squelch = v;	}; 	field_squelch.set_value(30);
+	field_squelch.on_change = [this](int32_t v) {	squelch = v;	}; 	field_squelch.set_value(-10);
 	field_volume.set_value((receiver_model.headphone_volume() - audio::headphone::volume_range().max).decibel() + 99);
 	field_volume.on_change = [this](int32_t v) { this->on_headphone_volume_changed(v);	};
 	// LEARN FREQUENCIES
@@ -417,7 +414,7 @@ void ScannerView::on_statistics_update(const ChannelStatistics& statistics) {
 		} 
 		else if (!timer) 
 		{
-			if (statistics.max_db > -squelch) {  		//There is something on the air...
+			if (statistics.max_db > squelch ) {  		//There is something on the air...(statistics.max_db > -squelch) 
 				if (scan_thread->is_freq_lock() >= MAX_FREQ_LOCK) { //checking time reached
 					scan_pause();
 					timer++;	
@@ -511,7 +508,6 @@ size_t ScannerView::change_mode(uint8_t new_mod) { //Before this, do a scan_thre
 	}
 
 	return mod_step[new_mod];
-
 }
 
 void ScannerView::start_scan_thread() {

firmware/application/apps/ui_scanner.hpp

@@ -142,7 +142,7 @@ private:
 	
 	Labels labels {
 		{ { 0 * 8, 0 * 16 }, "LNA:   VGA:   AMP:  VOL:", Color::light_grey() },
-		{ { 0 * 8, 1* 16 }, "BW:    SQUELCH:  /99 WAIT:", Color::light_grey() },
+		{ { 0 * 8, 1* 16 }, "BW:    SQUELCH:   db WAIT:", Color::light_grey() },
 		{ { 3 * 8, 10 * 16 }, "START        END     MANUAL", Color::light_grey() },
 		{ { 0 * 8, (26 * 8) + 4 }, "MODE:", Color::light_grey() },
 		{ { 11 * 8, (26 * 8) + 4 }, "STEP:", Color::light_grey() },
@@ -176,8 +176,8 @@ private:
 
 	NumberField field_squelch {
 		{ 15 * 8, 1 * 16 },
-		2,
+		3,
-		{ 0, 99 },
+ 		{ -90, 20 },
 		1,
 		' ',
 	};