implement sweep standby configuration

Software/VNA_embedded/Application/App.cpp

@@ -183,6 +183,11 @@ inline void App_Process() {
 					Communication::SendWithoutPayload(Protocol::PacketType::Ack);
 				}
 					break;
+				case Protocol::PacketType::InitiateSweep: {
+					VNA::InitiateSweep();
+					Communication::SendWithoutPayload(Protocol::PacketType::Ack);
+				}
+					break;
 				case Protocol::PacketType::SetIdle:
 					HW::SetMode(HW::Mode::Idle);
 					sweepActive = false;
@@ -314,7 +319,7 @@ inline void App_Process() {
 				}
 			}
 		}
-		if(HW::TimedOut()) {
+		if(!VNA::GetStandbyMode() && HW::TimedOut()) {
 			HW::SetMode(HW::Mode::Idle);
 			// insert the last received packet (restarts the timed out operation)
 			Communication::BlockNextAck();

Software/VNA_embedded/Application/Communication/Protocol.cpp

@@ -125,6 +125,7 @@ uint16_t Protocol::EncodePacket(const PacketInfo &packet, uint8_t *dest, uint16_
     case PacketType::ClearTrigger:
     case PacketType::StopStatusUpdates:
     case PacketType::StartStatusUpdates:
+    case PacketType::InitiateSweep:
         // no payload
         break;
     case PacketType::VNADatapoint: payload_size = packet.VNAdatapoint->requiredBufferSize(); break;

Software/VNA_embedded/Application/Communication/Protocol.hpp

@@ -159,7 +159,7 @@ using SweepSettings = struct _sweepSettings {
     uint16_t points;
     uint32_t if_bandwidth;
     int16_t cdbm_excitation_start; // in 1/100 dbm
-	uint16_t unused:1;
+	uint16_t standby:1;
 	uint16_t syncMaster:1;
 	uint16_t suppressPeaks:1;
 	uint16_t fixedPowerSetting:1; // if set the attenuator and source PLL power will not be changed across the sweep
@@ -366,6 +366,7 @@ enum class PacketType : uint8_t {
 	ClearTrigger = 29,
 	StopStatusUpdates = 30,
 	StartStatusUpdates = 31,
+	InitiateSweep = 32
 };
 
 using PacketInfo = struct _packetinfo {

Software/VNA_embedded/Application/VNA.cpp

@@ -258,12 +258,26 @@ bool VNA::Setup(Protocol::SweepSettings s) {
 	// Enable new data and sweep halt interrupt
 	FPGA::EnableInterrupt(FPGA::Interrupt::NewData);
 	FPGA::EnableInterrupt(FPGA::Interrupt::SweepHalted);
-	// Start the sweep
+	// Start the sweep if not configured for standby
 	firstPoint = true;
-	FPGA::StartSweep();
+	if(!settings.standby){
+		FPGA::StartSweep();
+	}
 	return true;
 }
 
+void VNA::InitiateSweep() {
+	// Invoked by a host via InitiateSweep packet
+	if(settings.standby){
+		// make sure that SweepSettings have been configured for standby operation
+		FPGA::StartSweep();
+	}
+}
+
+bool VNA::GetStandbyMode() {
+	return settings.standby;
+}
+
 static void PassOnData() {
 	Protocol::PacketInfo info;
 	info.type = Protocol::PacketType::VNADatapoint;
@@ -330,8 +344,11 @@ void VNA::Work() {
 		Communication::Send(packet);
 	}
 	// do not reset unlevel flag here, as it is calculated only once at the setup of the sweep
-	// Start next sweep
-	FPGA::StartSweep();
+	// Start next sweep if not configured for standby
+	if (!settings.standby){
+		FPGA::StartSweep();
+	}
+
 }
 
 void VNA::SweepHalted() {

Software/VNA_embedded/Application/VNA.hpp

@@ -7,6 +7,8 @@
 namespace VNA {
 
 bool Setup(Protocol::SweepSettings s);
+void InitiateSweep();
+bool GetStandbyMode();
 bool MeasurementDone(const FPGA::SamplingResult &result);
 void Work();
 void SweepHalted();