Add LED matrix to the proximity demo example

Author: AlexJones0

examples/all/proximity_sensor_example.cc

@@ -4,6 +4,7 @@
 // This examples requires a APDS9960 sensor
 // (https://www.adafruit.com/product/3595) connected to the qwiic0 connector.
 
+#include "../../libraries/sense_hat.hh"
 #include <compartment.h>
 #include <ctype.h>
 #include <debug.hh>
@@ -20,6 +21,8 @@ const uint8_t ApdS9960Pdata  = 0x9C;
 const uint8_t ApdS9960IdExp      = 0xAB;
 const uint8_t ApdS9960I2cAddress = 0x39;
 
+#define SENSE_HAT_AVAILABLE false
+
 /// Expose debugging features unconditionally for this compartment.
 using Debug = ConditionalDebug<true, "proximity sensor example">;
 
@@ -108,30 +111,72 @@ static uint8_t read_proximity_sensor(Mmio<OpenTitanI2c> i2c)
 	return buf[0];
 }
 
+void update_sense_hat(SenseHat *senseHat, uint8_t prox)
+{
+	constexpr uint8_t RedOffset   = 3u; // Minimum R on Sense HAT LEDs.
+	constexpr uint8_t ColourRange = SenseHat::Colour::MaxRedValue - RedOffset;
+	constexpr uint8_t ProxOffset  = 16u; // Minimum prox to show on LEDs.
+	constexpr uint8_t ProxRange   = UINT8_MAX - ProxOffset;
+	constexpr uint8_t NumLeds     = 8u * 8u;
+	constexpr SenseHat::Colour OffColour = {.red = 0U, .green = 0U, .blue = 0U};
+
+	SenseHat::Colour fb[NumLeds] = {OffColour};
+	/* Scale the proximity to the number of LED Matrix pixels. Clamp and
+	linearly scale the proximity / brightness scales for a better result. */
+	prox = (prox < ProxOffset) ? 0u : prox - ProxOffset;
+	uint8_t filled =
+	  static_cast<uint8_t>(static_cast<uint64_t>(prox) * NumLeds / ProxRange);
+	filled = (filled > NumLeds) ? NumLeds : filled;
+	for (uint8_t i = 0; i < filled; i++)
+	{
+		uint8_t red = static_cast<uint8_t>(
+		  static_cast<uint64_t>(i) * ColourRange / NumLeds + RedOffset);
+		fb[i] = (SenseHat::Colour){.red = red, .green = 0u, .blue = 0u};
+	}
+	senseHat->set_pixels(fb);
+}
+
 [[noreturn]] void __cheri_compartment("proximity_sensor_example") run()
 {
+	// Initialise the Sense HAT if we use it in this demo
+	SenseHat *senseHat = NULL;
+	if (SENSE_HAT_AVAILABLE)
+	{
+		senseHat = new SenseHat();
+	}
+
 	auto i2cSetup = [](Mmio<OpenTitanI2c> i2c) {
 		i2c->reset_fifos();
 		i2c->host_mode_set();
 		i2c->speed_set(1);
 	};
 
-	auto i2c1 = MMIO_CAPABILITY(OpenTitanI2c, i2c1);
-	i2cSetup(i2c1);
+	auto i2c0 = MMIO_CAPABILITY(OpenTitanI2c, i2c0);
+	i2cSetup(i2c0);
 	uint8_t addr;
 
 	auto rgbled = MMIO_CAPABILITY(SonataRgbLedController, rgbled);
 
-	setup_proximity_sensor(i2c1, ApdS9960I2cAddress);
+	setup_proximity_sensor(i2c0, ApdS9960I2cAddress);
 
 	while (true)
 	{
-		uint8_t prox = read_proximity_sensor(i2c1);
+		uint8_t prox = read_proximity_sensor(i2c0);
 		Debug::log("Proximity is {}\r", prox);
 		rgbled->rgb(SonataRgbLed::Led0, ((prox) >> 3), 0, 0);
 		rgbled->rgb(SonataRgbLed::Led1, 0, (255 - prox) >> 3, 0);
 		rgbled->update();
 
+		if (SENSE_HAT_AVAILABLE)
+		{
+			update_sense_hat(senseHat, prox);
+		}
+
 		thread_millisecond_wait(100);
 	}
+
+	if (SENSE_HAT_AVAILABLE)
+	{
+		delete senseHat;
+	}
 }

examples/all/xmake.lua

@@ -20,7 +20,7 @@ compartment("rgbled_lerp")
     add_files("rgbled_lerp.cc")
 
 compartment("proximity_sensor_example")
-    add_deps("debug")
+    add_deps("debug", "sense_hat")
     add_files("proximity_sensor_example.cc")
 
 compartment("sense_hat_demo")

examples/xmake.lua

@@ -115,7 +115,7 @@ firmware("sonata_proximity_demo")
                 compartment = "proximity_sensor_example",
                 priority = 2,
                 entry_point = "run",
-                stack_size = 0x200,
+                stack_size = 0x1000,
                 trusted_stack_frames = 1
             }
         }, {expand = false})
@@ -131,7 +131,7 @@ firmware("proximity_test")
                 compartment = "proximity_sensor_example",
                 priority = 2,
                 entry_point = "run",
-                stack_size = 0x200,
+                stack_size = 0x1000,
                 trusted_stack_frames = 1
             }
         }, {expand = false})