RTC works, 5V needed

Core/Inc/ds1307.h

@@ -11,7 +11,7 @@
 #define DS1307_H_
 
 #include "i2c.h"
-#include "DBG.h"
+//#include "DBG.h"
 
 
 typedef enum {

Core/Inc/i2c.h

@@ -0,0 +1,52 @@
+/* USER CODE BEGIN Header */
+/**
+  ******************************************************************************
+  * @file    i2c.h
+  * @brief   This file contains all the function prototypes for
+  *          the i2c.c file
+  ******************************************************************************
+  * @attention
+  *
+  * Copyright (c) 2026 STMicroelectronics.
+  * All rights reserved.
+  *
+  * This software is licensed under terms that can be found in the LICENSE file
+  * in the root directory of this software component.
+  * If no LICENSE file comes with this software, it is provided AS-IS.
+  *
+  ******************************************************************************
+  */
+/* USER CODE END Header */
+/* Define to prevent recursive inclusion -------------------------------------*/
+#ifndef __I2C_H__
+#define __I2C_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Includes ------------------------------------------------------------------*/
+#include "main.h"
+
+/* USER CODE BEGIN Includes */
+
+/* USER CODE END Includes */
+
+extern I2C_HandleTypeDef hi2c1;
+
+/* USER CODE BEGIN Private defines */
+
+/* USER CODE END Private defines */
+
+void MX_I2C1_Init(void);
+
+/* USER CODE BEGIN Prototypes */
+
+/* USER CODE END Prototypes */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __I2C_H__ */
+

Core/Inc/stm32f1xx_hal_conf.h

@@ -46,7 +46,7 @@
 /*#define HAL_ETH_MODULE_ENABLED   */
 /*#define HAL_FLASH_MODULE_ENABLED   */
 #define HAL_GPIO_MODULE_ENABLED
-/*#define HAL_I2C_MODULE_ENABLED   */
+#define HAL_I2C_MODULE_ENABLED
 /*#define HAL_I2S_MODULE_ENABLED   */
 /*#define HAL_IRDA_MODULE_ENABLED   */
 /*#define HAL_IWDG_MODULE_ENABLED   */