New RTC library implementation

libraries/RTC/RTC.h

@@ -0,0 +1,87 @@
+// RTC.h
+#pragma once
+
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/counter.h>
+#include <zephyr/drivers/rtc.h>
+#include <time.h>
+
+// Alarm callback types
+typedef void (*RTCAlarmCallback)(void *user_data);
+typedef void (*RTCUpdateCallback)(void *user_data);
+
+class ArduinoRTC {
+public:
+    ArduinoRTC();
+    bool begin();
+    ~ArduinoRTC();
+
+    /* setters */
+    bool setDayOfMonth(int day);
+    bool setMonthOfYear(int m);
+    bool setYear(int year);
+    bool setHour(int hour);
+    bool setMinute(int minute);
+    bool setSecond(int second);
+
+    /* Getters */
+    int getDayOfMonth();
+    int getMonth();
+    int getYear();
+    int getHour();
+    int getMinutes();
+    int getSeconds();
+
+    int setTime(int year, int month, int day, int hour, int minute, int second);
+    int getTime(int &year, int &month, int &day, int &hour, int &minute, int &second);
+#if defined(ARDUINO_GIGA) || defined(ARDUINO_PORTENTA_H7) || defined(ARDUINO_OPTA)
+    int setAlarm(int year, int month, int day, int hour, int minute, int second,
+                 RTCAlarmCallback cb = nullptr, void *user_data = nullptr);
+    int cancelAlarm();
+#elif defined(ARDUINO_NANO33BLE) || defined(ARDUINO_NICLA_SENSE_ME)
+    int setAlarm(int year, int month, int day, int hour, int minute, int second,
+                void (*callback)(const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data),
+                void *cb_user_data);
+    void cancelAlarm();
+#endif
+
+#if defined(ARDUINO_GIGA) || defined(ARDUINO_PORTENTA_H7) || defined(ARDUINO_OPTA)
+    // Optional APIs (only if supported)
+    int getAlarm(int &year, int &month, int &day, int &hour, int &minute, int &second);
+    bool isAlarmPending();
+    int setUpdateCallback(RTCUpdateCallback cb, void *user_data);
+    int setCalibration(int32_t calibration);
+    int getCalibration(int32_t &calibration);
+#endif
+
+
+private:
+#if defined(ARDUINO_GIGA) || defined(ARDUINO_PORTENTA_H7) || defined(ARDUINO_OPTA)
+    const struct device *rtc_dev;
+
+    static void alarmCallbackWrapper(const struct device *dev, uint16_t id, void *user_data);
+    static void updateCallbackWrapper(const struct device *dev, void *user_data);
+
+    RTCAlarmCallback userAlarmCallback = nullptr;
+    void *userAlarmCallbackData = nullptr;
+
+    RTCUpdateCallback userUpdateCallback = nullptr;
+    void *userUpdateCallbackData = nullptr;
+
+    uint16_t alarmId = 0; // default to alarm ID 0
+#elif defined(ARDUINO_NANO33BLE) || defined(ARDUINO_NICLA_SENSE_ME)
+    const struct device *counter_dev;
+    time_t timeOffset;
+
+    // Alarm members
+    struct counter_alarm_cfg alarm_cfg;
+    void (*user_callback)(const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data);
+    void *user_data;
+
+    static void alarmHandler(const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data);
+
+    time_t datetimeToEpoch(int year, int month, int day, int hour, int minute, int second);
+    void epochToDatetime(time_t t, int &year, int &month, int &day, int &hour, int &minute, int &second);
+#endif
+};

libraries/RTC/examples/AlarmRTC/AlarmRTC.ino

@@ -0,0 +1,76 @@
+/*
+* This sketch sets an alarm 10 seconds in the future and handles it via a callback.
+*/
+
+#include "RTC.h"
+#include <stdio.h>
+
+ArduinoRTC rtc;
+
+char printBuffer[30]; // declare a buffer of large enough size for the message we want to display
+int year, month, day, hour, minute, second;
+
+#if defined(ARDUINO_NICLA_SENSE_ME) || defined(ARDUINO_NANO33BLE)
+void onAlarm(const struct device *dev, uint8_t chan_id, uint32_t ticks, void *user_data) {
+    char printBuffer[40];
+    // Assuming user_data is a string or message you want to print
+    sprintf(printBuffer, "Alarm went off! Message: %s\n", (char *)user_data);
+    Serial.println(printBuffer);
+}
+#elif
+void onAlarm(void *user_data) {
+    char printBuffer[40];
+    sprintf(printBuffer, "Alarm went off! Message: %s\n", (char *)user_data);
+    Serial.println(printBuffer);
+}
+#endif
+
+void setup() {
+    int ret = 0xDEADBEEFu; // Starting with a custom value for the return which will definitely lead to failure if not changed to zero (i.e. success) by the functions below
+    char printBuffer[60];
+    Serial.begin(115200);
+    delay(1000);
+
+    if (!rtc.begin()) {
+        Serial.println("RTC not ready\n");
+        return;
+    }
+
+    int year, month, day, hour, minute, second;
+    ret = rtc.getTime(year, month, day, hour, minute, second);
+    if(ret != 0)
+    {
+        rtc.setTime(2025, 10, 21, 12, 0, 0);
+    }
+
+    sprintf(printBuffer, "Current Time: %04d-%02d-%02d %02d:%02d:%02d\n", year, month, day, hour, minute, second);
+    Serial.println(printBuffer);
+
+    // Set alarm 10 seconds into the future
+    second += 5;
+    // Correct for minute rollover if necessary
+    if (second >= 60) {
+        second -= 60;
+        minute += 1;
+    }
+
+    // The method also allows for registering a function callback which will be called when the alarm sets off and a display message which will be shown in the console
+    ret = rtc.setAlarm(year, month, day, hour, minute, second, onAlarm, (void *)"Wake up!!!");
+    if (ret == 0) {
+        sprintf(printBuffer, "Alarm set for: %02d:%02d:%02d\n", hour, minute, second);
+        Serial.println(printBuffer);
+    } else {
+        sprintf(printBuffer, "Failed to set alarm (%d)\n", ret);
+        Serial.println(printBuffer);
+    }
+}
+
+void loop() {
+    char printBuffer[30]; // declare a buffer of large enough size for the message we want to display
+    int y, m, d, h, min, s;
+    int status = rtc.getTime(y, m, d, h, min, s);
+    // Because the print() and println() functions do not support formatted output directly, we can use this trick to prepare a buffer with the string we want to show
+    sprintf(printBuffer, "Time is: %04d-%02d-%02d %02d:%02d:%02d", y, m, d, h, min, s);
+    Serial.println(printBuffer);
+    delay(1000);
+}

libraries/RTC/examples/CalibrationRTC/CalibrationRTC.ino

@@ -0,0 +1,40 @@
+#include "RTC.h"
+#include <stdio.h>
+
+// Doesn't work on the Opta for some reason.
+
+
+ArduinoRTC rtc;
+
+void setup() {
+    char printBuffer[30];
+    delay(1000);
+    Serial.begin(115200);
+    if (!rtc.begin()) {
+        printf("RTC not ready\n");
+        return;
+    }
+
+    int calib = 0;
+    if (rtc.getCalibration(calib) == 0) {
+        sprintf(printBuffer, "Current calibration: %d\n", calib);
+        Serial.println(printBuffer);
+    } else {
+        Serial.println("Failed to get calibration");
+    }
+
+    // Apply a small positive calibration (e.g., +1)
+    // This value is hardware-dependent, in a real application you should check the microcontroller's datasheet for the correct amount.
+    int32_t new_calib = calib + 1;
+
+    if (rtc.setCalibration(new_calib) == 0) {
+        sprintf(printBuffer, "Calibration updated to: %d\n", new_calib);
+        Serial.println(printBuffer);
+    } else {
+        Serial.println("Failed to set calibration");
+    }
+}
+
+void loop() {
+    delay(5000);
+}

libraries/RTC/examples/EnhancedRTC/EnhancedRTC.ino

@@ -0,0 +1,72 @@
+#include "RTC.h"
+
+ArduinoRTC rtc;
+
+// 7-segment style representation for digits 0–9 and colon ":"
+const char* bigDigits[11][3] = {
+    {" _ ", "| |", "|_|"}, // 0
+    {"   ", "  |", "  |"}, // 1
+    {" _ ", " _|", "|_ "}, // 2
+    {" _ ", " _|", " _|"}, // 3
+    {"   ", "|_|", "  |"}, // 4
+    {" _ ", "|_ ", " _|"}, // 5
+    {" _ ", "|_ ", "|_|"}, // 6
+    {" _ ", "  |", "  |"}, // 7
+    {" _ ", "|_|", "|_|"}, // 8
+    {" _ ", "|_|", " _|"}, // 9
+    {"   ", " . ", " . "}  // colon ":"
+};
+
+void printBigTime(int h, int m, int s) {
+    // Format time as HH:MM:SS string
+    char timeStr[9];
+    memset(timeStr, 0, sizeof(timeStr));
+    char bigDigitsPrint[40];
+    memset(bigDigitsPrint, 0, sizeof(bigDigitsPrint));
+    snprintf(timeStr, sizeof(timeStr), "%02d:%02d:%02d", h, m, s); // This (and further such manipulations) is necessary because Serial.print() does not support formatted output like printf()
+    Serial.println(timeStr);
+
+
+    // Print each of the 3 lines row by row
+    for (int row = 0; row < 3; row++) {
+        for (int i = 0; timeStr[i] != '\0'; i++) {
+            char c = timeStr[i];
+            if (c >= '0' && c <= '9') {
+                sprintf(bigDigitsPrint, "%s ", bigDigits[c - '0'][row]);
+                Serial.print(bigDigitsPrint);
+            } else if (c == ':') {
+                sprintf(bigDigitsPrint, "%s ", bigDigits[10][row]);
+                Serial.print(bigDigitsPrint);
+            } else {
+                Serial.print("    "); // Space or unknown
+            }
+        }
+        Serial.println();
+    }
+     Serial.println();
+}
+
+void setup() {
+    Serial.begin(115200);
+    rtc.begin();
+    bool status = rtc.setTime(2025, 9, 25, 7, 46, 0);  // Initial time
+}
+
+void loop() {
+    int y, m, d, h, min, s;
+    char printBuffer[60]; 
+    int status = rtc.getTime(y, m, d, h, min, s);
+
+    // Clear screen (optional line, works on many terminals, tested on Tera Term. Does not take effect in Arduino IDE console unfortunately)
+    Serial.println("\033[2J\033[H");
+
+    // Print date and time in plain format
+    sprintf(printBuffer, "Date: %04d-%02d-%02d\n", y, m, d);
+    Serial.println(printBuffer);
+    Serial.println("Time:");
+
+    // Print time in big digits
+    printBigTime(h, min, s);
+
+    delay(1000);
+}

libraries/RTC/examples/SimpleRTC/SimpleRTC.ino

@@ -0,0 +1,23 @@
+#include "RTC.h"
+
+ArduinoRTC rtc;
+
+int year, month, day, hour, minute, second;
+int previousSecond = 0;
+char printBuffer[30];               // Allocate large enough buffer to hold the 28 characters of the output format "Time is: 2025-09-25 11:49:26"
+
+void setup() {
+    Serial.begin(115200);
+    if (!rtc.begin()) {
+        Serial.println("RTC not ready\n");
+        return;
+    }
+    rtc.setTime(2025, 10, 21, 12, 0, 0);
+}
+
+void loop() {
+    rtc.getTime(year, month, day, hour, minute, second);    // Read back time from hardware
+    sprintf(printBuffer, "Time is: %04d-%02d-%02d %02d:%02d:%02d", year, month, day, hour, minute, second);
+    Serial.println(printBuffer);
+    delay(1000);
+}

variants/arduino_giga_r1_stm32h747xx_m7/arduino_giga_r1_stm32h747xx_m7.conf

@@ -23,6 +23,12 @@ CONFIG_DAC=y
 CONFIG_PWM=y
 CONFIG_I2C_TARGET=y
 
+CONFIG_CLOCK_CONTROL=y
+CONFIG_RTC=y
+CONFIG_RTC_ALARM=y
+CONFIG_RTC_UPDATE=y
+CONFIG_RTC_CALIBRATION=y
+
 CONFIG_ICACHE=y
 CONFIG_DCACHE=y
 CONFIG_CACHE_MANAGEMENT=y

variants/arduino_giga_r1_stm32h747xx_m7/arduino_giga_r1_stm32h747xx_m7.overlay

@@ -27,6 +27,17 @@
 	status = "okay";
 };
 
+&rtc {
+    status = "okay";
+    label = "RTC_0";
+
+    clocks = <&rcc STM32_CLOCK_BUS_APB1 0x10000000>,  /* RTCAPB */
+             <&rcc STM32_SRC_LSE RTC_SEL(1)>;         /* Use LSI instead of LSE */
+
+    alarms-count = <2>;
+    alrm-exti-line = <17>;
+};
+
 &i2c4 {
 	status = "okay";
 	gc2145: gc2145@3c {

variants/arduino_nano_33_ble_nrf52840_sense/arduino_nano_33_ble_nrf52840_sense.conf

@@ -25,6 +25,7 @@ CONFIG_CDC_ACM_DTE_RATE_CALLBACK_SUPPORT=y
 
 CONFIG_ADC=y
 CONFIG_PWM=y
+CONFIG_COUNTER=y
 
 CONFIG_LLEXT_STORAGE_WRITABLE=n
 CONFIG_SHELL_STACK_SIZE=2048

variants/arduino_nano_33_ble_nrf52840_sense/arduino_nano_33_ble_nrf52840_sense.overlay

@@ -273,3 +273,8 @@
 	clock-frequency = <I2C_BITRATE_FAST>;
 };
 
+&rtc2 {
+    status = "okay";
+    clock-frequency = <32768>;
+    prescaler = <1>;  // Optional: sets the RTC tick to ~30.5 µs
+};

variants/arduino_nano_33_ble_nrf52840_sense/arduino_nano_33_ble_sense.overlay

@@ -196,3 +196,8 @@
 	pinctrl-1 = <&pwm2_sleep>;
 	pinctrl-names = "default", "sleep";
 };
+
+&rtc2 {
+    status = "okay";
+    prescaler = <1>;  // Optional: sets the RTC tick to ~30.5 µs
+};

variants/arduino_nicla_sense_me_nrf52832/arduino_nicla_sense_me_nrf52832.conf

@@ -18,12 +18,13 @@ CONFIG_BT_BUF_CMD_TX_COUNT=10
 
 #CONFIG_ADC=y
 #CONFIG_PWM=y
+CONFIG_COUNTER=y
 
 CONFIG_LLEXT_STORAGE_WRITABLE=n
 CONFIG_SHELL_STACK_SIZE=1024
 CONFIG_HEAP_MEM_POOL_SIZE=1024
 CONFIG_LLEXT_HEAP_SIZE=15
-CONFIG_MAIN_STACK_SIZE=1024
+CONFIG_MAIN_STACK_SIZE=2048
 
 CONFIG_BT_RX_STACK_SIZE=1024
 CONFIG_BT_HCI_TX_STACK_SIZE=1024

variants/arduino_nicla_sense_me_nrf52832/arduino_nicla_sense_me_nrf52832.overlay

@@ -7,6 +7,12 @@
 	};
 };
 
+&rtc2 {
+    status = "okay";
+    clock-frequency = <32768>;
+    prescaler = <1>;  // Optional: sets the RTC tick to ~30.5 µs
+};
+
 / {
 	zephyr,user {
 		digital-pin-gpios = <&gpio0 10 0>,		// 0: GPIO3
@@ -34,4 +40,4 @@
 		i2cs = <&i2c1>;
 		spis = <&spi1>;
 	};
-};
+};