[iwdg] Add initialize() with prescaler calculator

Author: salkinium

examples/nucleo_f072rb/independend_watchdog/main.cpp renamed to examples/nucleo_f072rb/iwdg/main.cpp

@@ -13,6 +13,7 @@
 #include <modm/platform.hpp>
 
 using namespace Board;
+using namespace std::chrono_literals;
 
 /**
  * If the button is pressed for more than 4 seconds, the MCU will be reset by the Watchdog.
@@ -25,7 +26,7 @@ main()
 	Board::initialize();
 	LedD13::setOutput();
 	// set the watchdog timeout to 4 seconds
-	Iwdg::initialize(Iwdg::Prescaler::Div32, 0x0FFFu);
+	Iwdg::initialize<SystemClock, 4s>();
 
 	// Use the logging streams to print some messages.
 	// Change MODM_LOG_LEVEL above to enable or disable these messages

examples/nucleo_f072rb/independend_watchdog/project.xml renamed to examples/nucleo_f072rb/iwdg/project.xml

@@ -84,13 +84,21 @@ class PeripheralDriver
 	 * This method checks if the user requested baudrate is within error
 	 * tolerance of the system achievable baudrate.
 	 */
-	template< baudrate_t available, baudrate_t requested, percent_t tolerance >
+	template< uint64_t available, uint64_t requested, percent_t tolerance >
 	static void
 	assertBaudrateInTolerance()
 	{
 		static_assert(modm::isValueInTolerance(requested, available, tolerance),
 				"The closest available baudrate exceeds the tolerance of the requested baudrate!");
 	}
+
+	template< double available, double requested, percent_t tolerance >
+	static void
+	assertDurationInTolerance()
+	{
+		static_assert(modm::isValueInTolerance(requested, available, tolerance),
+				"The closest available duration exceeds the tolerance of the requested duration!");
+	}
 };
 
 } // namespace modm

src/modm/architecture/interface/peripheral.hpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2023, Zühlke Engineering (Austria) GmbH
+ * Copyright (c) 2024, Niklas Hauser
  *
  * This file is part of the modm project.
  *
@@ -10,14 +11,16 @@
 // ----------------------------------------------------------------------------
 
 #pragma once
+#include <modm/architecture/interface/peripheral.hpp>
+#include <modm/math/algorithm/prescaler_counter.hpp>
 #include "../device.hpp"
 
 
 namespace modm::platform
 {
 
 /// @ingroup modm_platform_iwdg
-class Iwdg
+class Iwdg : public ::modm::PeripheralDriver
 {
 public:
 	enum class
@@ -43,15 +46,19 @@ class Iwdg
 	};
 
 public:
-	static inline void
-	initialize(Prescaler prescaler, uint32_t reload)
+	template< class SystemClock, milliseconds_t timeout, percent_t tolerance=pct(1) >
+	static void
+	initialize()
 	{
-		writeKey(writeCommand);
-		IWDG->PR = uint32_t(prescaler);
-		IWDG->RLR = reload;
-		writeKey(0); // disable access to PR and RLR registers
+		constexpr double frequency = 1000.0 / timeout.count();
+		constexpr auto result = modm::GenericPrescalerCounter<double>::from_power(
+			SystemClock::Iwdg, frequency, 1ul << 12, 256, 4);
+		assertDurationInTolerance< 1.0 / result.frequency, 1.0 / frequency, tolerance >();
+
+		configure(Prescaler(result.index), result.counter - 1);
 	}
 
+
 	static inline void
 	enable()
 	{
@@ -71,15 +78,24 @@ class Iwdg
 	}
 
 private:
-	static constexpr uint16_t reloadCommand = 0xAAAA;
-	static constexpr uint16_t writeCommand = 0x5555;
-	static constexpr uint16_t enableCommand = 0xCCCC;
+	static inline void
+	configure(Prescaler prescaler, uint16_t reload)
+	{
+		writeKey(writeCommand);
+		IWDG->PR = uint32_t(prescaler);
+		IWDG->RLR = reload;
+		writeKey(0); // disable access to PR and RLR registers
+	}
 
 	static inline void
 	writeKey(uint16_t key)
 	{
 		IWDG->KR = key;
 	}
+
+	static constexpr uint16_t reloadCommand = 0xAAAA;
+	static constexpr uint16_t writeCommand = 0x5555;
+	static constexpr uint16_t enableCommand = 0xCCCC;
 };
 
 }

src/modm/platform/iwdg/stm32/iwdg.hpp

@@ -21,7 +21,7 @@ def prepare(module, options):
     if device.identifier.family in ["h7"]:
         return False
 
-    module.depends(":cmsis:device")
+    module.depends(":cmsis:device", ":math:algorithm")
     return device.has_driver("iwdg:stm32")