[example] Add DAC example for SAMV71 Xplained Ultra board

Author: chris-durand

examples/samv71_xplained_ultra/dac/main.cpp

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2023, Christopher Durand
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+
+using namespace Board;
+
+/**
+ * Simple DAC example
+ *
+ * Output sawtooth waveform in free-running mode.
+ *
+ * See DMA examples for use of DAC with DMA.
+ */
+
+using Out0 = GpioB13;
+
+void waitForTxReady()
+{
+	while (!(Dac::readInterruptFlags() & Dac::Interrupt::TxReadyCh0));
+}
+
+int main()
+{
+	Board::initialize();
+
+	Dac::connect<Out0::Ch0>();
+	Dac::initialize<SystemClock, 12_MHz>();
+
+	Dac::enableChannel(Dac::Channel::Channel0);
+
+	while (true)
+	{
+		for (int i = 0; i <= 4095; ++i)
+		{
+			waitForTxReady();
+			Dac::setOutput0(i);
+		}
+	}
+
+	return 0;
+}

examples/samv71_xplained_ultra/dac/project.xml

@@ -0,0 +1,10 @@
+<library>
+  <extends>modm:samv71-xplained-ultra</extends>
+  <options>
+    <option name="modm:build:build.path">../../../build/samv71_xplained_ultra/dac</option>
+  </options>
+  <modules>
+    <module>modm:build:scons</module>
+    <module>modm:platform:dac</module>
+  </modules>
+</library>

src/modm/board/samv71_xplained_ultra/board.hpp

@@ -32,6 +32,7 @@ struct SystemClock
 	static constexpr uint32_t Usart1 = Mck;
 	static constexpr uint32_t Spi0 = Mck;
 	static constexpr uint32_t Twihs0 = Mck;
+	static constexpr uint32_t Dacc = Mck;
 //	static constexpr uint32_t Usb = 48_MHz;
 
 	static bool inline