STM32-DS3231

Simple and Intuitive STM32 I2C HAL library for the DS3231 RTC

Still in active development as there are still many routines yet to be implemented, Contributions are highly welcome!

Contributing

A few notes:

We adhere strictly to the Google C++ Style Guidelines.

Datasheet can be found HERE (Really Helpful).

Example

It is advisable to use 400kHz frequency for the I2C.
Also, be sure to set the configuration of the I2C (rise and fall time especially) as described in the datasheet to get consistent results.
Just provide the Rx and Tx routines and you're good to go! A really easy interface as demonstrated below:

extern "C" {
#include "main.h"

#include <stdio.h>
#include "stm32f7xx_hal_i2c.h"
#include "stm32f7xx_hal_uart.h"
}

#include "DS3231.h"

extern "C" I2C_HandleTypeDef hi2c1;

extern "C" UART_HandleTypeDef huart3;

ds3231::Status RtcReceive(uint8_t* buffer, uint16_t size,
                          ds3231::duration_type timeout) {
  return static_cast<ds3231::Status>(HAL_I2C_Master_Receive(
      &hi2c1, 0b1101000 << 1, buffer, size, timeout.count()));
}

ds3231::Status RtcTransmit(const uint8_t* buffer, uint16_t size,
                           ds3231::duration_type timeout) {
  return static_cast<ds3231::Status>(HAL_I2C_Master_Transmit(
      &hi2c1, 0b1101000 << 1, const_cast<uint8_t*>(buffer), size,
      timeout.count()));
}

extern "C" int cxx_main() {
  printf("Started\n");

  ds3231::I2cInterface interface;
  interface.rx = RtcReceive;
  interface.tx = RtcTransmit;
  const auto timeout = ds3231::duration_type{500};
  ds3231::DS3231 rtc{interface};
  printf("Resetting...\n");
  auto rstatus = rtc.Reset(timeout);

  if (rstatus == ds3231::Status::Ok) {
    printf("Ctrl Reset\n");

  } else {
    printf("Unable to Reset\n");
  }

  auto s_status = rtc.SecondsFunc(30, timeout);
  auto m_status = rtc.MinutesFunc(59, timeout);
  auto h_status = rtc.HoursFunc(4, timeout);
  if (s_status == ds3231::Status::Ok && m_status == ds3231::Status::Ok &&
      h_status == ds3231::Status::Ok) {
    printf("Time set\n");
  } else {
    printf("Unable to set time\n");
  }
  HAL_Delay(500);
  while (true) {
    HAL_Delay(1000);
    auto res_s = rtc.SecondsFunc(timeout);
    auto res_m = rtc.MinutesFunc(timeout);
    auto res_h = rtc.HoursFunc(timeout);
    if (res_s.second == ds3231::Status::Ok &&
        res_m.second == ds3231::Status::Ok &&
        res_h.second == ds3231::Status::Ok) {
      printf("[Main:Daemon:Rtc] %u:%u:%u\n", res_h.first, res_m.first,
             res_s.first);
    } else {
      printf("[Main:Daemon:Rtc] Unable to get time\n");
    }
  }
  return 0;
}

You should get something like this:

Installation

Copy the header files from the Inc directory and the source files from the Src directory into the appropriate sections of your STM32 project.

License

Apache License 2.0