stm32L0xx or stm32L1xx soc series has an embedded EEPROM

This EEPROM area is mapped in the non volatile memory
and accessed with dedicated HAL functions
In this case, the EEPROM area is defined
from DATA_EEPROM_BASE to DATA_EEPROM_END

Signed-off-by: Francois Ramu <francois.ramu@st.com>

Author: FRASTM

cores/arduino/stm32/stm32_eeprom.h

@@ -80,7 +80,25 @@ extern "C" {
  */
 #define FLASH_PAGE_SIZE     ((uint32_t)(16*1024)) /* 16kB page */
 #endif
+
+#if defined(DATA_EEPROM_BASE) || defined(FLASH_EEPROM_BASE)
+
+#if defined (DATA_EEPROM_END)
+#define E2END (DATA_EEPROM_END - DATA_EEPROM_BASE)
+#elif defined (DATA_EEPROM_BANK2_END)
+/* assuming two contiguous banks */
+#define DATA_EEPROM_END DATA_EEPROM_BANK2_END
+#define E2END (DATA_EEPROM_BANK2_END - DATA_EEPROM_BASE)
+#elif defined (FLASH_EEPROM_END)
+#define DATA_EEPROM_BASE FLASH_EEPROM_BASE
+#define DATA_EEPROM_END FLASH_EEPROM_END
+#define E2END (DATA_EEPROM_END - DATA_EEPROM_BASE)
+#endif /* __EEPROM_END */
+
+#else /* _EEPROM_BASE */
 #define E2END (FLASH_PAGE_SIZE - 1)
+#endif /* _EEPROM_BASE */
+
 #endif
 
 /* Exported macro ------------------------------------------------------------*/

libraries/SrcWrapper/src/stm32/stm32_eeprom.c

@@ -151,8 +151,19 @@ static uint8_t eeprom_buffer[E2END + 1] __attribute__((aligned(8))) = {0};
   */
 uint8_t eeprom_read_byte(const uint32_t pos)
 {
+#if defined(DATA_EEPROM_BASE)
+  __IO uint8_t data = 0;
+  if (pos <= (DATA_EEPROM_END - DATA_EEPROM_BASE)) {
+    /* with actual EEPROM, pos is a relative address */
+    data = *(__IO uint8_t *)(DATA_EEPROM_BASE + pos);
+    /* align content of the buffered eeprom */
+    eeprom_buffer[pos] = (uint8_t)data;
+  }
+  return (uint8_t)data;
+#else
   eeprom_buffer_fill();
   return eeprom_buffered_read_byte(pos);
+#endif /* _EEPROM_BASE */
 }
 
 /**
@@ -163,8 +174,20 @@ uint8_t eeprom_read_byte(const uint32_t pos)
   */
 void eeprom_write_byte(uint32_t pos, uint8_t value)
 {
+#if defined(DATA_EEPROM_BASE)
+  /* with actual EEPROM, pos is a relative address */
+  if (pos <= (DATA_EEPROM_END - DATA_EEPROM_BASE)) {
+    if (HAL_FLASHEx_DATAEEPROM_Unlock() == HAL_OK) {
+      HAL_FLASHEx_DATAEEPROM_Program(FLASH_TYPEPROGRAMDATA_BYTE, (pos + DATA_EEPROM_BASE), (uint32_t)value);
+      HAL_FLASHEx_DATAEEPROM_Lock();
+    }
+  }
+  /* align content of the buffered eeprom */
+  eeprom_buffer[pos] = (uint8_t)value;
+#else
   eeprom_buffered_write_byte(pos, value);
   eeprom_buffer_flush();
+#endif /* _EEPROM_BASE */
 }
 
 /**