better typing, better use of std::span

Author: TomSaw

src/modm/driver/motion/adns9800.hpp

@@ -17,6 +17,7 @@
 #include <modm/architecture/interface/spi_device.hpp>
 #include <modm/architecture/interface/accessor_flash.hpp>
 #include <modm/debug/logger.hpp>
+#include <modm/ui/color/brightness.hpp>
 
 EXTERN_FLASH_STORAGE(uint8_t adns9800_firmware[3070]);
 
@@ -103,7 +104,9 @@ struct adns9800 {
   MODM_FLAGS8(ConfigurationII);
 
 
+  using Color = modm::color::Brightness;
   static constexpr size_t FrameSize = 30 * 30;
+  using FrameBuffer = std::array<Color, FrameSize>;
 
   // Time periods as ticks of Adns9800 running at 50MHz
   using PeriodType = uint16_t;
@@ -317,26 +320,30 @@ class Adns9800 : public adns9800, public modm::SpiDevice<SpiMaster> {
   requires std::is_base_of_v<Data, D>
   D
   read() {
-    std::array<uint8_t, D::length> buffer;
+    std::array<uint8_t, D::Span::extent> buffer;
 
     readTransaction([this, &buffer]() {
       SpiMaster::transfer(static_cast<uint8_t>(Register::Motion_Burst));
       modm::this_fiber::sleep_for(shutter_config.getOneFrameTime());
-      SpiMaster::transfer(nullptr, std::begin(buffer), buffer.size());
+      SpiMaster::transfer(nullptr, buffer.data(), buffer.size());
     });
 
     return D(buffer);
   }
 
   // @todo test captureFrame
-  void
-  captureFrame(std::span<uint8_t, FrameSize> buffer) {
+  FrameBuffer
+  captureFrame() {
+    FrameBuffer buffer{};
+
     readTransaction([&buffer]() {
       writeRegister(Register::Frame_Capture, 0x93);
       writeRegister(Register::Frame_Capture, 0xc5);
       modm::this_fiber::poll(readRegister(Register::Motion) & Bit0); // wait for first pixel
-      SpiMaster::transfer(nullptr, buffer, FrameSize);
+      SpiMaster::transfer(nullptr, buffer.data(), buffer.size());
     });
+
+    return buffer;
   }
 
 private:

src/modm/driver/motion/adns9800.lb

@@ -32,7 +32,8 @@ def prepare(module, options):
     module.depends(
         ":processing:resumable",
         ":architecture:spi.device",
-        ":math:geometry"
+        ":math:geometry",
+        ":ui:color"
         )
     return True
 

src/modm/driver/motion/adns9800_data.hpp

@@ -31,14 +31,15 @@ namespace modm
 /// @brief Relative motion since the last read
 struct adns9800::Data
 {
+	using Span = std::span<uint8_t, 6>;
+
 	const modm::Vector<DeltaType, 2> delta;
 
 protected:
-	static constexpr size_t length = 6;
-	Data(std::span<uint8_t, length> buffer)
+	Data(Span data)
 		: delta{
-      static_cast<DeltaType>(buffer[3] << 8 | buffer[2]),
-			static_cast<DeltaType>(buffer[5] << 8 | buffer[4])
+      static_cast<DeltaType>(data[3] << 8 | data[2]),
+			static_cast<DeltaType>(data[5] << 8 | data[4])
     }
 	{}
 
@@ -54,11 +55,11 @@ struct adns9800::Data_Fails : public adns9800::Data
 	const bool isRunningSROMCode : 1;
 
 protected:
-	Data_Fails(std::span<uint8_t, length> buffer)
-		: Data(buffer),
-		  LaserFaultDetected(buffer[0] & Bit6),
-		  LaserPowerValid(buffer[0] & Bit5),
-		  isRunningSROMCode(buffer[1] & Bit6)
+	Data_Fails(Span data)
+		: Data(data),
+		  LaserFaultDetected(data[0] & Bit6),
+		  LaserPowerValid(data[0] & Bit5),
+		  isRunningSROMCode(data[1] & Bit6)
 	{}
 
 	template<class, class>
@@ -68,6 +69,8 @@ struct adns9800::Data_Fails : public adns9800::Data
 /// @brief Relative motion, laser fault detection flags and metrics from the shutter unit.
 struct adns9800::Data_Fails_Monitoring : public adns9800::Data_Fails
 {
+	using Span = std::span<uint8_t, adns9800::Data_Fails::Span::extent + 8>;
+
 	struct Statistics
 	{
 		/**
@@ -83,12 +86,12 @@ struct adns9800::Data_Fails_Monitoring : public adns9800::Data_Fails
 		// frame
 		const uint8_t pixel_sum;
 		// Minium and maximum Pixel value in current frame. Range: 0 to 127.
-		const uint8_t max_pixel;
-		const uint8_t min_pixel;
+		const Color max_pixel;
+		const Color min_pixel;
 	} statistics;
 
-	uint8_t
-	getAveragePixelValue() const
+	Color
+	getAveragePixel() const
 	{
 		return statistics.pixel_sum << 9 / FrameSize;
 	}
@@ -113,18 +116,17 @@ struct adns9800::Data_Fails_Monitoring : public adns9800::Data_Fails
 	};
 
 protected:
-	static constexpr size_t length = 14;
-	Data_Fails_Monitoring(std::span<uint8_t, length> buffer)
-		: Data_Fails(buffer.subspan<0, Data_Fails::length>()),
+	Data_Fails_Monitoring(Span data)
+		: Data_Fails(data.subspan<0, Data_Fails::Span::extent>()),
 		  statistics{
-			  surface_quality : buffer[6],
-			  pixel_sum : buffer[7],
-			  max_pixel : buffer[8],
-			  min_pixel : buffer[9]
+			  surface_quality : data[6],
+			  pixel_sum : data[7],
+			  max_pixel : data[8],
+			  min_pixel : data[9]
 		  },
 		  shutter{
-			  exposure : static_cast<PeriodType>(buffer[10] << 8 | buffer[11]),
-			  period : static_cast<PeriodType>(buffer[12] << 8 | buffer[13])
+			  exposure : static_cast<PeriodType>(data[10] << 8 | data[11]),
+			  period : static_cast<PeriodType>(data[12] << 8 | data[13])
 		  }
 	{}