[example] Add small example using RCR register

examples/nucleo_f401re/timer_register_count/main.cpp

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+/*
+ * Copyright (c) 2023, Zühlke (Austria) gmbh
+ *
+ * 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/.
+ */
+
+// The Repetition count register combined with one pulse mode is a great
+// tool to enable the timer to produce a limited amount of pulses in PWM
+// mode. In this example Timer1 is configured to produce 50 PWM pulses
+// with 90% of duty cycle.
+
+#include <modm/architecture/interface/interrupt.hpp>
+#include <modm/board.hpp>
+#include <modm/platform.hpp>
+
+using namespace Board;
+
+volatile uint32_t counter(0);
+constexpr uint32_t number_of_pulses = 50;
+
+template<class Timer>
+void
+advancedTimerConfig()
+{
+	Timer::enable();
+	Timer::setMode(Timer::Mode::UpCounter, Timer::SlaveMode::Disabled,
+				   Timer::SlaveModeTrigger::Internal0, Timer::MasterMode::Update, true);
+	Timer::setPrescaler(84);
+	Timer::setOverflow(9999);
+	Timer::enableInterruptVector(Timer::Interrupt::CaptureCompare1, true, 0);
+	Timer::enableInterrupt(Timer::Interrupt::CaptureCompare1);
+	Timer::setRepetitionCount(number_of_pulses - 1);
+
+	Timer::enableOutput();
+	Timer::configureOutputChannel(1, Timer::OutputCompareMode::Pwm, 999, Timer::PinState::Enable);
+}
+
+template<class Timer>
+void
+timerStart()
+{
+	Timer::applyAndReset();
+	Timer::start();
+}
+
+MODM_ISR(TIM1_CC)
+{
+	modm::platform::Timer1::acknowledgeInterruptFlags(
+		modm::platform::Timer1::InterruptFlag::CaptureCompare1);
+	LedD13::toggle();
+	counter++;
+}
+
+int
+main()
+{
+	Board::initialize();
+	LedD13::setOutput();
+
+	// Use the logging streams to print some messages.
+	// Change MODM_LOG_LEVEL above to enable or disable these messages
+	MODM_LOG_DEBUG << "debug" << modm::endl;
+	MODM_LOG_INFO << "info" << modm::endl;
+	MODM_LOG_WARNING << "warning" << modm::endl;
+	MODM_LOG_ERROR << "error" << modm::endl;
+
+	advancedTimerConfig<Timer1>();
+	timerStart<Timer1>();
+
+	while (true)
+	{
+		MODM_LOG_DEBUG << "Timer 1 pulsed " << static_cast<uint8_t>(counter) << "times\r"
+					   << modm::endl;
+		modm::delay(0.5s);
+	}
+
+	return 0;
+}

examples/nucleo_f401re/timer_register_count/project.xml

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+<library>
+  <extends>modm:nucleo-f401re</extends>
+  <options>
+    <option name="modm:build:build.path">../../../build/nucleo_f401re/timer_register_count</option>
+  </options>
+  <modules>
+    <module>modm:build:scons</module>
+    <module>modm:platform:timer:1</module>
+  </modules>
+</library>