Provide WDT backed reset for ArduinoCore-renesas.

Author: aentinger

examples/AsyncReset/AsyncReset.ino

@@ -27,7 +27,12 @@ void setup()
   while (!Serial) { }
 
   Serial.println("Trigger async reset in 5 seconds ...");
-  cyphal::support::platform::reset_async(std::chrono::milliseconds(5000));
+  auto const rc = cyphal::support::platform::reset_async(std::chrono::milliseconds(5000));
+  if (rc.has_value()) {
+    Serial.print("reset_async failed with error code ");
+    Serial.println(static_cast<int>(rc.value()));
+  }
+
   start = millis();
 }
 

examples/SyncReset/SyncReset.ino

@@ -21,7 +21,11 @@ void setup()
   while (!Serial) { }
 
   Serial.println("Trigger sync reset in 5 seconds ...");
-  cyphal::support::platform::reset_sync(std::chrono::milliseconds(5000));
+  auto const rc = cyphal::support::platform::reset_sync(std::chrono::milliseconds(5000));
+  if (rc.has_value()) {
+    Serial.print("reset_sync failed with error code ");
+    Serial.println(static_cast<int>(rc.value()));
+  }
 }
 
 void loop()

src/reset/reset-renesas.cpp

@@ -0,0 +1,89 @@
+/**
+ * This software is distributed under the terms of the MIT License.
+ * Copyright (c) 2023 LXRobotics.
+ * Author: Alexander Entinger <[email protected]>
+ * Contributors: https://github.com/107-systems/107-Arduino-Cyphal-Support/graphs/contributors.
+ */
+
+/**************************************************************************************
+ * INCLUDE
+ **************************************************************************************/
+
+#include "reset.h"
+
+#if defined(ARDUINO_ARCH_RENESAS)
+
+#include <WDT.h>
+
+/* Provide prototype for Arduino's delay function. */
+extern "C" void delay(unsigned long);
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+namespace cyphal::support::platform
+{
+
+/**************************************************************************************
+ * GLOBAL CONSTANTS
+ **************************************************************************************/
+
+#if defined(ARDUINO_MINIMA) || defined(ARDUINO_UNOWIFIR4)
+static uint32_t const WATCHDOG_MAX_DELAY_ms = 5592;
+#elif defined(ARDUINO_PORTENTA_C33)
+static uint32_t const WATCHDOG_MAX_DELAY_ms = 2684;
+#else
+# error "Your selected Renesas MCU is not supported"
+#endif
+
+/**************************************************************************************
+ * GLOBAL VARIABLES
+ **************************************************************************************/
+
+static bool is_async_reset_pending_flag = false;
+
+/**************************************************************************************
+ * FUNCTION DEFINITION
+ **************************************************************************************/
+
+std::optional<Error> reset()
+{
+  WDT.begin(1); /* Minium delay is 1 ms. */
+  return std::nullopt;
+}
+
+std::optional<Error> reset_sync(std::chrono::milliseconds const ms)
+{
+  if (ms.count() > WATCHDOG_MAX_DELAY_ms)
+    return Error::InvalidParam;
+
+  WDT.begin(ms.count());
+  for(;;) { delay(100); } /* Wait for the watchdog to bite. */
+  return std::nullopt;
+}
+
+std::optional<Error> reset_async(std::chrono::milliseconds const ms)
+{
+  if (ms.count() > WATCHDOG_MAX_DELAY_ms)
+    return Error::InvalidParam;
+
+  WDT.begin(ms.count());
+
+  is_async_reset_pending_flag = true;
+
+  return std::nullopt;
+}
+
+bool is_async_reset_pending()
+{
+  return is_async_reset_pending_flag;
+}
+
+/**************************************************************************************
+ * NAMESPACE
+ **************************************************************************************/
+
+} /* cyphal::support::platform */
+
+#endif /* defined(ARDUINO_ARCH_RENESAS) */

src/reset/reset.h

@@ -39,26 +39,26 @@ enum class Error
 
 /* Immediately after calling this method a reset is performed. */
 std::optional<Error> reset()
-#if !defined(ARDUINO_ARCH_RP2040)
-__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040.")))
+#if !defined(ARDUINO_ARCH_RP2040) && !defined(ARDUINO_ARCH_RENESAS)
+__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040 and ARDUINO_ARCH_RENESAS.")))
 #endif
 ;
 
 /* This method performs a reset in 'ms' milliseconds after its invocation,
  * blocking while waiting for the time to expire.
  */
 std::optional<Error> reset_sync(std::chrono::milliseconds const ms)
-#if !defined(ARDUINO_ARCH_RP2040)
-__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040.")))
+#if !defined(ARDUINO_ARCH_RP2040) && !defined(ARDUINO_ARCH_RENESAS)
+__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040 and ARDUINO_ARCH_RENESAS.")))
 #endif
 ;
 
 /* This method performs a reset in 'ms' milliseconds after its invocation,
  * but returns immediately after its invocation.
  */
 std::optional<Error> reset_async(std::chrono::milliseconds const ms)
-#if !defined(ARDUINO_ARCH_RP2040)
-__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040.")))
+#if !defined(ARDUINO_ARCH_RP2040) && !defined(ARDUINO_ARCH_RENESAS)
+__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040 and ARDUINO_ARCH_RENESAS.")))
 #endif
 ;
 
@@ -67,8 +67,8 @@ __attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040
  * regular watchdog feeding i.e. in the main loop.
  */
 bool is_async_reset_pending()
-#if !defined(ARDUINO_ARCH_RP2040)
-__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040.")))
+#if !defined(ARDUINO_ARCH_RP2040) && !defined(ARDUINO_ARCH_RENESAS)
+__attribute__ ((error("Currently the reset API only supports ARDUINO_ARCH_RP2040 and ARDUINO_ARCH_RENESAS.")))
 #endif
 ;