[driver] iwr6843aop class member buffers to reduce stack usage

Author: hshose

examples/nucleo_h723zg/iwr6843aop/main.cpp

@@ -26,7 +26,8 @@ using DataRx = GpioC11;
 using RadarNrst = GpioC9;
 
 using Radar = modm::Iwr6843aop<ControlUart, DataUart>;
-static Radar radar;
+Radar radar;
+Radar::FrameType radarFrame{};
 
 static constexpr char RadarConfiguration[] = R"cfg(
 sensorStop
@@ -95,7 +96,6 @@ main()
 
 	MODM_LOG_INFO << "Configuration successful\n";
 
-	Radar::FrameType frame{};
 	modm::Timestamp lastFrameTimestamp{};
 	bool hasLastFrameTimestamp{false};
 	uint32_t processedFrames{0};
@@ -110,35 +110,35 @@ main()
 			modm::delay(5ms);
 		}
 
-		while (radar.getFrame(frame))
+		while (radar.getFrame(radarFrame))
 		{
 			processedFrames++;
 			LedGreen::toggle();
 
 			const auto now = modm::Clock::now();
-			const auto age = now - frame.timestamp;
+			const auto age = now - radarFrame.timestamp;
 
 			uint32_t intervalMs{0};
 			if (hasLastFrameTimestamp)
 			{
-				intervalMs = (frame.timestamp - lastFrameTimestamp).count();
+				intervalMs = (radarFrame.timestamp - lastFrameTimestamp).count();
 			}
-			lastFrameTimestamp = frame.timestamp;
+			lastFrameTimestamp = radarFrame.timestamp;
 			hasLastFrameTimestamp = true;
 
 			float maxVelocity{0.f};
-			for (std::size_t ii = 0; ii < frame.pointCount; ++ii)
+			for (std::size_t ii = 0; ii < radarFrame.pointCount; ++ii)
 			{
-				float velocity = frame.points[ii].point.velocity;
+				float velocity = radarFrame.points[ii].point.velocity;
 				if (velocity < 0.f) { velocity = -velocity; }
 				if (velocity > maxVelocity) { maxVelocity = velocity; }
 			}
 
 			MODM_LOG_INFO.printf(
 				"Frame #%lu: %lu points detected, age: %lu ms, interval: %lu ms, max velocity: "
 				"%.2f m/s\n",
-				static_cast<unsigned long>(frame.frameHeader.frameNumber),
-				static_cast<unsigned long>(frame.pointCount),
+				static_cast<unsigned long>(radarFrame.frameHeader.frameNumber),
+				static_cast<unsigned long>(radarFrame.pointCount),
 				static_cast<unsigned long>(age.count()), static_cast<unsigned long>(intervalMs),
 				static_cast<double>(maxVelocity));
 

examples/nucleo_h723zg/iwr6843aop/project.xml

@@ -2,7 +2,6 @@
   <extends>modm:nucleo-h723zg</extends>
   <options>
     <option name="modm:build:build.path">../../../build/nucleo_h723zg/iwr6843aop</option>
-    <option name="modm:platform:cortex-m:main_stack_size">16Ki</option>
   </options>
   <modules>
     <module>modm:build:scons</module>

src/modm/driver/radar/iwr6843aop.hpp

@@ -322,6 +322,11 @@ class Iwr6843aop : public iwr6843aop
 
 	Error lastError_{Error::None};
 
+	std::array<char, MaxConfigLineLength> configCommandBuffer_{};
+	std::array<char, MaxResponseLineLength> responseLineBuffer_{};
+	std::array<uint8_t, DataReadChunkSize> dataReadChunk_{};
+	FrameType parserFrame_{};
+
 	std::array<uint8_t, MaxParserBufferSize> parserBuffer_{};
 	std::size_t parserSize_{0};
 

src/modm/driver/radar/iwr6843aop_impl.hpp

@@ -74,7 +74,7 @@ bool
 Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 		   MaxParserBufferSize>::configure(std::span<const char> configuration)
 {
-	std::array<char, MaxConfigLineLength> command{};
+	auto &command = configCommandBuffer_;
 	std::size_t commandLength{0};
 
 	auto executeCommand = [&](std::size_t length) -> bool {
@@ -176,7 +176,7 @@ bool
 Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 		   MaxParserBufferSize>::waitForCommandResponse(bool verifyDone, CommandResponse *response)
 {
-	std::array<char, MaxResponseLineLength> currentLine{};
+	auto &currentLine = responseLineBuffer_;
 	std::size_t currentLineLength{0};
 
 	bool seenDone{false};
@@ -254,13 +254,12 @@ Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 {
 	maybeTriggerSyncPulse();
 
-	std::array<uint8_t, DataReadChunkSize> chunk{};
 	while (true)
 	{
-		const auto bytesRead = DataUart::read(chunk.data(), chunk.size());
+		const auto bytesRead = DataUart::read(dataReadChunk_.data(), dataReadChunk_.size());
 		if (bytesRead == 0) { break; }
 
-		if (not appendData(chunk.data(), bytesRead)) { return false; }
+		if (not appendData(dataReadChunk_.data(), bytesRead)) { return false; }
 	}
 
 	if (DataUart::hasError())
@@ -457,8 +456,7 @@ Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 
 		if (parserSize_ < totalPacketLength) { return true; }
 
-		FrameType frame{};
-		if (not parsePacket(parserBuffer_.data(), totalPacketLength, frame))
+		if (not parsePacket(parserBuffer_.data(), totalPacketLength, parserFrame_))
 		{
 			setError(Error::ParseError);
 			if (not registerParseError()) { return false; }
@@ -467,7 +465,7 @@ Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 		}
 
 		consecutiveParseErrorCount_ = 0;
-		enqueueFrame(frame);
+		enqueueFrame(parserFrame_);
 		dropBytes(totalPacketLength);
 	}
 }
@@ -764,4 +762,4 @@ Iwr6843aop<ControlUart, DataUart, SyncPin, FrameQueueSize, MaxPointsPerFrame,
 	return value;
 }
 
-}  // namespace modm
+}  // namespace modm