[stm32] Adding Real Time Clock (RTC) for STM32G4

README.md

@@ -445,6 +445,30 @@ Please [discover modm's peripheral drivers for your specific device][discover].
 <td align="center">✕</td>
 <td align="center">✕</td>
 </tr><tr>
+<td align="left">RTC</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">✅</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">○</td>
+<td align="center">✕</td>
+<td align="center">✕</td>
+<td align="center">✕</td>
+</tr><tr>
 <td align="left">SPI</td>
 <td align="center">✅</td>
 <td align="center">✅</td>

examples/nucleo_g474re/rtc/main.cpp

@@ -0,0 +1,63 @@
+// coding: utf-8
+/*
+ * Copyright (c) 2023, Rasmus Kleist Hørlyck Sørensen
+ *
+ * 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>
+#include <modm/debug/logger.hpp>
+#include <modm/platform.hpp>
+#include <modm/processing.hpp>
+
+using namespace modm::literals;
+
+// Set the log level
+#undef	MODM_LOG_LEVEL
+#define	MODM_LOG_LEVEL modm::log::INFO
+
+static constexpr Rtc::DateTime datetime = {
+	.year = 0,
+	.month = 12,
+	.date = 31,
+	.weekday = 1,
+	.hour = 23,
+	.minute = 59,
+	.second = 30,
+};
+
+int
+main()
+{
+	Board::initialize();
+
+	modm::PeriodicTimer timer(std::chrono::milliseconds(1000));
+
+	Rtc::initialize<Board::SystemClock>();
+	while (true)
+	{
+		if (timer.execute())
+		{
+			float ss;
+			Rtc::DateTime dt;
+			if (Rtc::getSubSecond(ss) && Rtc::getDateTime(dt))
+			{
+				MODM_LOG_INFO << "Date: " << dt.date << "-" << dt.month << "-" << dt.year << modm::endl;
+				MODM_LOG_INFO << "Weekday: " << dt.weekday << modm::endl;
+				MODM_LOG_INFO << "Time: " << dt.hour << ":" << dt.minute << ":" << dt.second << modm::endl;
+				MODM_LOG_INFO << "Sub Second: " << ss << modm::endl;
+			}
+			else
+			{
+				MODM_LOG_INFO << "Error: Unable to get Date Time and Sub Second" << modm::endl;
+			}
+		}
+	}
+
+	return 0;
+}

examples/nucleo_g474re/rtc/project.xml

@@ -0,0 +1,12 @@
+<library>
+	<extends>modm:nucleo-g474re</extends>
+	<options>
+		<option name="modm:build:build.path">../../../build/nucleo_g474re/rtc</option>
+	</options>
+	<modules>
+		<module>modm:debug</module>
+		<module>modm:platform:rtc</module>
+		<module>modm:processing:timer</module>
+		<module>modm:build:scons</module>
+	</modules>
+</library>

src/modm/board/nucleo_g474re/board.hpp

@@ -114,6 +114,9 @@ struct SystemClock
 		// update frequencies for busy-wait delay functions
 		Rcc::updateCoreFrequency<Frequency>();
 
+		Rcc::enableLowSpeedExternalCrystal();
+    	Rcc::enableRealTimeClock(Rcc::RealTimeClockSource::LowSpeedExternalCrystal);
+
 		Rcc::setCanClockSource(Rcc::CanClockSource::Pclk);
 		return true;
 	}

src/modm/math/utils.hpp

@@ -22,5 +22,6 @@
 #include "utils/operator.hpp"
 #include "utils/endianness.hpp"
 #include "utils/crc.hpp"
+#include "utils/bcd.hpp"
 
 #endif // MODM_MATH_UTILS_HPP

src/modm/math/utils/bcd.hpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2023, Rasmus Kleist Hørlyck Sørensen
+ *
+ * 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/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_MATH_BCD_HPP
+#define MODM_MATH_BCD_HPP
+
+#include <stdint.h>
+
+namespace modm
+{
+
+/// @ingroup modm_math_utils
+/// @{
+
+constexpr uint32_t
+fromBcd(uint32_t bcd)
+{
+    uint32_t decimal = 0;
+    for (uint16_t multiplier = 1; bcd != 0; multiplier *= 10)
+    {
+        decimal += (bcd & 0b1111) * multiplier;
+        bcd >>= 4;
+    }
+    return decimal;
+}
+
+constexpr uint32_t
+toBcd(uint32_t decimal)
+{
+    uint32_t bcd = 0;
+    uint16_t remainder = decimal % 10;
+    for (uint16_t shift = 0; decimal != 0; shift += 4)
+    {
+        bcd |= remainder << shift;
+        decimal = (decimal - remainder) / 10;
+        remainder = decimal % 10;
+    }
+    return bcd;
+}
+
+/// @}
+
+} // namespace modm
+
+#endif	// MODM_MATH_BCD_HPP

src/modm/platform/clock/stm32/module.lb

@@ -179,6 +179,9 @@ def build(env):
             nper = "DSI"
         if "Eth" in all_peripherals and per == "ETHMAC":
             per = "Eth"
+        if "Rtc" in all_peripherals and per == "RTCAPB":
+            per = "RTC"
+            nper = "RTCAPB"
         # Fix USBOTG OTG
         if target.family == "u5" and per == "OTG":
             per = "Usbotgfs"
@@ -193,7 +196,9 @@ def build(env):
         if per.capitalize() not in all_peripherals:
             continue
         if "EN" in mode:
-            rcc_enable[per.capitalize()] = (nper, mode["EN"])
+            kw = per.capitalize()
+            if kw not in rcc_enable:
+                rcc_enable[kw] = (nper, mode["EN"])
         if "RST" in mode:
             rcc_reset[nper] = mode["RST"]
 

src/modm/platform/clock/stm32/rcc_impl.hpp.in

@@ -167,4 +167,4 @@ Rcc::isEnabled()
 	%% endfor
 }
 
-}   // namespace modm::platform
+}   // namespace modm::platform

src/modm/platform/core/stm32/startup_platform.c.in

@@ -61,6 +61,8 @@ __modm_initialize_platform(void)
 	// Enable Data Tighly Coupled Memory (DTCM) and backup SRAM (BKPSRAM)
 	RCC->AHB1ENR |= RCC_AHB1ENR_DTCMRAMEN | RCC_AHB1ENR_BKPSRAMEN;
 %% elif target.family in ["g0", "g4", "l4", "l5"]
+	// Enable access to RTC and Backup registers
+	PWR->CR1 |= PWR_CR1_DBP;
 %% if target.family in ["l4", "g4"]
 	RCC->APB1ENR1 |= RCC_APB1ENR1_PWREN;
 %% elif target.family != "g0"

src/modm/platform/rtc/stm32/module.lb

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2023, Rasmus Kleist Hørlyck Sørensen
+#
+# 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/.
+# -----------------------------------------------------------------------------
+
+def init(module):
+    module.name = ":platform:rtc"
+    module.description = "Real Time Clock (RTC)"
+
+def prepare(module, options):
+    device = options[":target"]
+    if device.identifier.family not in ["g4"]:
+        return False
+    if not device.has_driver("rtc:stm32*"):
+        return False
+
+    module.depends(
+        ":cmsis:device",
+        ":platform:rcc",
+        ":architecture:register",
+        ":math:utils",
+        ":math:units",)
+
+    return True
+
+def build(env):
+    target = env[":target"].identifier
+
+    env.outbasepath = "modm/src/modm/platform/rtc"
+    env.template("rtc_impl.hpp.in")
+    env.template("rtc.cpp.in")
+    env.template("rtc.hpp.in")

src/modm/platform/rtc/stm32/rtc.cpp.in

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2023, Rasmus Kleist Hørlyck Sørensen
+ *
+ * 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 "rtc.hpp"
+
+#include <modm/math/utils.hpp>
+
+namespace modm::platform
+{
+
+// ----------------------------------------------------------------------------
+
+bool
+Rtc::getDateTime(DateTime &dateTime, uint32_t waitCycles)
+{
+    /// TODO: Determine if ABP1 frequency is less than seven times RTC frequency
+    /// TODO: Determine if BYPSHAD control bit is set or cleared in the RTC_CR register
+
+    // After initialization, synchronization software must wait until RSF is set
+    while (!(RTC->ICSR & RTC_ICSR_RSF))
+        if (--waitCycles == 0) return false;
+
+    dateTime.hour     = fromBcd((RTC->TR & (RTC_TR_HT_Msk | RTC_TR_HU_Msk)) >> RTC_TR_HU_Pos);
+    dateTime.minute   = fromBcd((RTC->TR & (RTC_TR_MNT_Msk | RTC_TR_MNU_Msk)) >> RTC_TR_MNU_Pos);
+    dateTime.second   = fromBcd((RTC->TR & (RTC_TR_ST_Msk | RTC_TR_SU_Msk)) >> RTC_TR_SU_Pos);
+
+    dateTime.year     = fromBcd((RTC->DR & (RTC_DR_YT_Msk | RTC_DR_YU_Msk)) >> RTC_DR_YU_Pos);
+    dateTime.month    = fromBcd((RTC->DR & (RTC_DR_MT_Msk | RTC_DR_MU_Msk)) >> RTC_DR_MU_Pos);
+    dateTime.date     = fromBcd((RTC->DR & (RTC_DR_DT_Msk | RTC_DR_DU_Msk)) >> RTC_DR_DU_Pos);
+    dateTime.weekday  = ((RTC->DR & RTC_DR_WDU_Msk) >> RTC_DR_WDU_Pos);
+
+    return true;
+}
+
+// ----------------------------------------------------------------------------
+
+bool
+Rtc::getSubSecond(float &subsecond, uint32_t waitCycles)
+{
+    // After initialization, synchronization software must wait until RSF is set
+    while (!(RTC->ICSR & RTC_ICSR_RSF))
+        if (--waitCycles == 0) return false;
+
+    /*
+    uint32_t predivS = getSynchronousPrescaler();
+    uint32_t ss = (RTC->SSR & RTC_SSR_SS_Msk) >> RTC_SSR_SS_Pos;
+    subsecond = float(predivS - ss) / float(predivS + 1);
+    /// TODO: Handle case when ss > predivS
+    */
+    return true;
+}
+
+}