ESP32 DS1302 Real-Time Clock (RTC)

Code Examples

Below you can find code examples of DS1302 Real-Time Clock (RTC) with ESP32 in several frameworks:

• Arduino IDE
• ESP-IDF
• ESPHome
• PlatformIO
• MicroPython

If you encounter issues while using the DS1302 Real-Time Clock (RTC), check the Common Issues Troubleshooting Guide.

ESP32 DS1302 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the DS1302 Real-Time Clock (RTC):

#include <DS1302.h>

DS1302 rtc(19, 21, 22); // RST, I/O, SCLK

void setup() {
    Serial.begin(9600);
    rtc.halt(false);
    rtc.writeProtect(false);
    rtc.setDateTime(2023, 12, 4, 14, 30, 0); // Set initial date/time: YYYY, MM, DD, HH, MM, SS
}

void loop() {
    DS1302::DateTime now = rtc.getDateTime();
    Serial.print("Time: ");
    Serial.print(now.hour);
    Serial.print(":");
    Serial.print(now.minute);
    Serial.print(":");
    Serial.println(now.second);
    Serial.print("Date: ");
    Serial.print(now.year);
    Serial.print("/");
    Serial.print(now.month);
    Serial.print("/");
    Serial.println(now.day);
    delay(1000);
}

This Arduino sketch demonstrates how to use the DS1302 RTC module for timekeeping with updated pins (RST: GPIO19, DAT: GPIO21, CLK: GPIO22). The DS1302 library simplifies communication with the RTC. The setDateTime() function initializes the RTC with a specific date and time. In the loop(), the current date and time are fetched and displayed on the Serial Monitor.

Connect your ESP32 to your computer via a USB cable, Ensure the correct Board and Port are selected under Tools, Click the "Upload" button in the Arduino IDE to compile and upload the code to your ESP32.

ESP32 DS1302 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the DS1302 Real-Time Clock (RTC), here's how you can set it up and read data from the sensor. Fill in this code in the main ESP-IDF file:

#include <stdio.h>
#include "driver/gpio.h"
#include "ds1302.h"

void app_main(void) {
    ds1302_config_t config = {
        .rst_pin = GPIO_NUM_19,
        .io_pin = GPIO_NUM_21,
        .sclk_pin = GPIO_NUM_22
    };
    ds1302_init(&config);
    ds1302_set_datetime(2023, 12, 4, 14, 30, 0);

    while (1) {
        ds1302_datetime_t now;
        ds1302_get_datetime(&now);
        printf("Time: %02d:%02d:%02d\n", now.hour, now.minute, now.second);
        printf("Date: %04d/%02d/%02d\n", now.year, now.month, now.day);
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

This ESP-IDF example initializes the DS1302 RTC with updated pins (RST: GPIO19, DAT: GPIO21, CLK: GPIO22). The RTC is set to an initial date and time, and in a loop, the current time is retrieved and printed every second using the ds1302_get_datetime() function.

Update the I2C pins (I2C_MASTER_SDA_IO and I2C_MASTER_SCL_IO) to match your ESP32 hardware setup, Use idf.py build to compile the project, Use idf.py flash to upload the code to your ESP32.

ESP32 DS1302 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the DS1302 Real-Time Clock (RTC)

uart:
  tx_pin: GPIO21
  rx_pin: GPIO22
  baud_rate: 9600

time:
  - platform: ds1302
    id: ds1302_time
    update_interval: 1s

sensor:
  - platform: custom
    lambda: |-
      auto my_sensor = new DS1302Sensor(id(ds1302_time));
      return {my_sensor};
    sensors:
      - name: "DS1302 Date and Time"

The ESPHome configuration for the DS1302 RTC defines the updated pins for UART communication (DAT: GPIO21, CLK: GPIO22). The time platform is used to interact with the RTC, and a custom sensor is defined to periodically retrieve and display the date and time. The update interval is set to 1 second for regular updates.

Upload this code to your ESP32 using the ESPHome dashboard or the esphome run command.

ESP32 DS1302 PlatformIO Code Example

Example in PlatformIO Framework

For PlatformIO, make sure to configure the platformio.ini file with the appropriate environment and libraries, and then proceed with the code.

Configure platformio.ini

First, your platformio.ini should look like below. You might need to include some libraries as shown. Make sure to change the board to your ESP32:

[env:arduino_uno]
platform = atmelavr
board = uno
framework = arduino
monitor_speed = 9600

ESP32 DS1302 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the DS1302 Real-Time Clock (RTC):

#include <DS1302.h>

DS1302 rtc(19, 21, 22); // RST, I/O, SCLK

void setup() {
    Serial.begin(9600);
    rtc.halt(false);
    rtc.writeProtect(false);
    rtc.setDateTime(2023, 12, 4, 14, 30, 0);
}

void loop() {
    DS1302::DateTime now = rtc.getDateTime();
    Serial.print("Time: ");
    Serial.print(now.hour);
    Serial.print(":");
    Serial.print(now.minute);
    Serial.print(":");
    Serial.println(now.second);
    Serial.print("Date: ");
    Serial.print(now.year);
    Serial.print("/");
    Serial.print(now.month);
    Serial.print("/");
    Serial.println(now.day);
    delay(1000);
}

The PlatformIO code has been updated for the DS1302 RTC with the new pin configuration (RST: GPIO19, DAT: GPIO21, CLK: GPIO22). The RTC is initialized with these pins, and the current time is fetched and displayed every second.

Upload the code to your ESP32 using the PlatformIO "Upload" button in your IDE or the pio run --target upload command.

ESP32 DS1302 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the DS1302 Real-Time Clock (RTC) with your ESP32.

from machine import Pin
import time

# Pin definitions
CLK = Pin(22, Pin.OUT)  # Clock pin
DAT = Pin(21, Pin.INOUT)  # Data pin
RST = Pin(19, Pin.OUT)  # Reset pin

# DS1302 commands
READ_TIME = 0x81
WRITE_TIME = 0x80

def write_byte(byte):
    for i in range(8):
        CLK.value(0)
        DAT.value((byte >> i) & 1)
        CLK.value(1)

def read_byte():
    result = 0
    for i in range(8):
        CLK.value(0)
        if DAT.value():
            result |= (1 << i)
        CLK.value(1)
    return result

def set_time(year, month, day, hour, minute, second):
    RST.value(1)
    write_byte(WRITE_TIME)
    write_byte(second)
    write_byte(minute)
    write_byte(hour)
    write_byte(day)
    write_byte(month)
    write_byte(year - 2000)
    RST.value(0)

def get_time():
    RST.value(1)
    write_byte(READ_TIME)
    second = read_byte()
    minute = read_byte()
    hour = read_byte()
    day = read_byte()
    month = read_byte()
    year = read_byte() + 2000
    RST.value(0)
    return year, month, day, hour, minute, second

# Initialize DS1302
RST.value(0)
CLK.value(0)

# Set initial time
set_time(2023, 12, 4, 14, 30, 0)

# Loop to read time
while True:
    year, month, day, hour, minute, second = get_time()
    print(f"Time: {hour:02}:{minute:02}:{second:02}, Date: {year:04}/{month:02}/{day:02}")
    time.sleep(1)

This MicroPython script communicates with the DS1302 RTC using a 3-wire serial protocol with CLK (GPIO22), DAT (GPIO21), and RST (GPIO19). The set_time() function initializes the DS1302 with the provided date and time by writing data byte-by-byte. The get_time() function reads the current date and time by issuing the appropriate commands and parsing the returned bytes. The main loop continuously fetches and prints the time and date every second.

Upload this code to your ESP32 using a MicroPython-compatible IDE, such as Thonny, uPyCraft, or tools like ampy.