STM32 EEPROM Emulation (#3741)

* STM32 EEPROM Emulation

- Added EEPROM emulation libaries from libmaple and Arduino_STM32. https://github.com/rogerclarkmelbourne/Arduino_STM32 and https://github.com/leaflabs/libmaple.
- Renamed teensy EEPROM library and added conditional selection of library.
- Remapped EEPROM memory map for 16 byte blocks (as is with STM32f3xx MCUs).
- Added EEPROM initialization in main.c of Chibios.
- Added EEPROM format to clear the emulated pages when EEPROM is marked as invalid.

* Fixed ifdef

9 files changed, 1035 insertions, 1 deletions

diff --git a/tmk_core/common.mk b/tmk_core/common.mk
index fd91d29dce..319d196aec 100644
--- a/tmk_core/common.mk
+++ b/tmk_core/common.mk
@@ -31,7 +31,12 @@ endif
 
 ifeq ($(PLATFORM),CHIBIOS)
 	TMK_COMMON_SRC += $(PLATFORM_COMMON_DIR)/printf.c
-	TMK_COMMON_SRC += $(PLATFORM_COMMON_DIR)/eeprom.c
+  ifeq ($(MCU_SERIES), STM32F3xx)
+    TMK_COMMON_SRC += $(PLATFORM_COMMON_DIR)/eeprom_stm32.c
+    TMK_COMMON_SRC += $(PLATFORM_COMMON_DIR)/flash_stm32.c
+  else
+    TMK_COMMON_SRC += $(PLATFORM_COMMON_DIR)/eeprom_teensy.c
+endif
   ifeq ($(strip $(AUTO_SHIFT_ENABLE)), yes)
     TMK_COMMON_SRC += $(CHIBIOS)/os/various/syscalls.c
   endif
diff --git a/tmk_core/common/chibios/eeprom_stm32.c b/tmk_core/common/chibios/eeprom_stm32.c
new file mode 100755
index 0000000000..3c19451223
--- /dev/null
+++ b/tmk_core/common/chibios/eeprom_stm32.c
@@ -0,0 +1,673 @@
+/*
+ * This software is experimental and a work in progress.
+ * Under no circumstances should these files be used in relation to any critical system(s).
+ * Use of these files is at your own risk.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and 
+ * https://github.com/leaflabs/libmaple
+ *
+ * Modifications for QMK and STM32F303 by Yiancar
+ */
+
+#include "eeprom_stm32.h"
+
+    FLASH_Status EE_ErasePage(uint32_t);
+
+    uint16_t EE_CheckPage(uint32_t, uint16_t);
+    uint16_t EE_CheckErasePage(uint32_t, uint16_t);
+    uint16_t EE_Format(void);
+    uint32_t EE_FindValidPage(void);
+    uint16_t EE_GetVariablesCount(uint32_t, uint16_t);
+    uint16_t EE_PageTransfer(uint32_t, uint32_t, uint16_t);
+    uint16_t EE_VerifyPageFullWriteVariable(uint16_t, uint16_t);
+
+    uint32_t PageBase0 = EEPROM_PAGE0_BASE;
+    uint32_t PageBase1 = EEPROM_PAGE1_BASE;
+    uint32_t PageSize = EEPROM_PAGE_SIZE;
+    uint16_t Status = EEPROM_NOT_INIT;
+
+// See http://www.st.com/web/en/resource/technical/document/application_note/CD00165693.pdf
+
+/**
+  * @brief  Check page for blank
+  * @param  page base address
+  * @retval Success or error
+  *     EEPROM_BAD_FLASH:   page not empty after erase
+  *     EEPROM_OK:          page blank
+  */
+uint16_t EE_CheckPage(uint32_t pageBase, uint16_t status)
+{
+    uint32_t pageEnd = pageBase + (uint32_t)PageSize;
+
+    // Page Status not EEPROM_ERASED and not a "state"
+    if ((*(__IO uint16_t*)pageBase) != EEPROM_ERASED && (*(__IO uint16_t*)pageBase) != status)
+        return EEPROM_BAD_FLASH;
+    for(pageBase += 4; pageBase < pageEnd; pageBase += 4)
+        if ((*(__IO uint32_t*)pageBase) != 0xFFFFFFFF)  // Verify if slot is empty
+            return EEPROM_BAD_FLASH;
+    return EEPROM_OK;
+}
+
+/**
+  * @brief  Erase page with increment erase counter (page + 2)
+  * @param  page base address
+  * @retval Success or error
+  *         FLASH_COMPLETE: success erase
+  *         - Flash error code: on write Flash error
+  */
+FLASH_Status EE_ErasePage(uint32_t pageBase)
+{
+    FLASH_Status FlashStatus;
+    uint16_t data = (*(__IO uint16_t*)(pageBase));
+    if ((data == EEPROM_ERASED) || (data == EEPROM_VALID_PAGE) || (data == EEPROM_RECEIVE_DATA))
+        data = (*(__IO uint16_t*)(pageBase + 2)) + 1;
+    else
+        data = 0;
+
+    FlashStatus = FLASH_ErasePage(pageBase);
+    if (FlashStatus == FLASH_COMPLETE)
+        FlashStatus = FLASH_ProgramHalfWord(pageBase + 2, data);
+
+    return FlashStatus;
+}
+
+/**
+  * @brief  Check page for blank and erase it
+  * @param  page base address
+  * @retval Success or error
+  *         - Flash error code: on write Flash error
+  *         - EEPROM_BAD_FLASH: page not empty after erase
+  *         - EEPROM_OK:            page blank
+  */
+uint16_t EE_CheckErasePage(uint32_t pageBase, uint16_t status)
+{
+    uint16_t FlashStatus;
+    if (EE_CheckPage(pageBase, status) != EEPROM_OK)
+    {
+        FlashStatus = EE_ErasePage(pageBase);
+        if (FlashStatus != FLASH_COMPLETE)
+            return FlashStatus;
+        return EE_CheckPage(pageBase, status);
+    }
+    return EEPROM_OK;
+}
+
+/**
+  * @brief  Find valid Page for write or read operation
+  * @param  Page0: Page0 base address
+  *         Page1: Page1 base address
+  * @retval Valid page address (PAGE0 or PAGE1) or NULL in case of no valid page was found
+  */
+uint32_t EE_FindValidPage(void)
+{
+    uint16_t status0 = (*(__IO uint16_t*)PageBase0);        // Get Page0 actual status
+    uint16_t status1 = (*(__IO uint16_t*)PageBase1);        // Get Page1 actual status
+
+    if (status0 == EEPROM_VALID_PAGE && status1 == EEPROM_ERASED)
+        return PageBase0;
+    if (status1 == EEPROM_VALID_PAGE && status0 == EEPROM_ERASED)
+        return PageBase1;
+
+    return 0;
+}
+
+/**
+  * @brief  Calculate unique variables in EEPROM
+  * @param  start: address of first slot to check (page + 4)
+  * @param  end: page end address
+  * @param  address: 16 bit virtual address of the variable to excluse (or 0XFFFF)
+  * @retval count of variables
+  */
+uint16_t EE_GetVariablesCount(uint32_t pageBase, uint16_t skipAddress)
+{
+    uint16_t varAddress, nextAddress;
+    uint32_t idx;
+    uint32_t pageEnd = pageBase + (uint32_t)PageSize;
+    uint16_t count = 0;
+
+    for (pageBase += 6; pageBase < pageEnd; pageBase += 4)
+    {
+        varAddress = (*(__IO uint16_t*)pageBase);
+        if (varAddress == 0xFFFF || varAddress == skipAddress)
+            continue;
+
+        count++;
+        for(idx = pageBase + 4; idx < pageEnd; idx += 4)
+        {
+            nextAddress = (*(__IO uint16_t*)idx);
+            if (nextAddress == varAddress)
+            {
+                count--;
+                break;
+            }
+        }
+    }
+    return count;
+}
+
+/**
+  * @brief  Transfers last updated variables data from the full Page to an empty one.
+  * @param  newPage: new page base address
+  * @param  oldPage: old page base address
+  * @param  SkipAddress: 16 bit virtual address of the variable (or 0xFFFF)
+  * @retval Success or error status:
+  *           - FLASH_COMPLETE: on success
+  *           - EEPROM_OUT_SIZE: if valid new page is full
+  *           - Flash error code: on write Flash error
+  */
+uint16_t EE_PageTransfer(uint32_t newPage, uint32_t oldPage, uint16_t SkipAddress)
+{
+    uint32_t oldEnd, newEnd;
+    uint32_t oldIdx, newIdx, idx;
+    uint16_t address, data, found;
+    FLASH_Status FlashStatus;
+
+    // Transfer process: transfer variables from old to the new active page
+    newEnd = newPage + ((uint32_t)PageSize);
+
+    // Find first free element in new page
+    for (newIdx = newPage + 4; newIdx < newEnd; newIdx += 4)
+        if ((*(__IO uint32_t*)newIdx) == 0xFFFFFFFF)    // Verify if element
+            break;                                  //  contents are 0xFFFFFFFF
+    if (newIdx >= newEnd)
+        return EEPROM_OUT_SIZE;
+
+    oldEnd = oldPage + 4;
+    oldIdx = oldPage + (uint32_t)(PageSize - 2);
+
+    for (; oldIdx > oldEnd; oldIdx -= 4)
+    {
+        address = *(__IO uint16_t*)oldIdx;
+        if (address == 0xFFFF || address == SkipAddress)
+            continue;                       // it's means that power off after write data
+
+        found = 0;
+        for (idx = newPage + 6; idx < newIdx; idx += 4)
+            if ((*(__IO uint16_t*)(idx)) == address)
+            {
+                found = 1;
+                break;
+            }
+
+        if (found)
+            continue;
+
+        if (newIdx < newEnd)
+        {
+            data = (*(__IO uint16_t*)(oldIdx - 2));
+
+            FlashStatus = FLASH_ProgramHalfWord(newIdx, data);
+            if (FlashStatus != FLASH_COMPLETE)
+                return FlashStatus;
+
+            FlashStatus = FLASH_ProgramHalfWord(newIdx + 2, address);
+            if (FlashStatus != FLASH_COMPLETE)
+                return FlashStatus;
+
+            newIdx += 4;
+        }
+        else
+            return EEPROM_OUT_SIZE;
+    }
+
+    // Erase the old Page: Set old Page status to EEPROM_EEPROM_ERASED status
+    data = EE_CheckErasePage(oldPage, EEPROM_ERASED);
+    if (data != EEPROM_OK)
+        return data;
+
+    // Set new Page status
+    FlashStatus = FLASH_ProgramHalfWord(newPage, EEPROM_VALID_PAGE);
+    if (FlashStatus != FLASH_COMPLETE)
+        return FlashStatus;
+
+    return EEPROM_OK;
+}
+
+/**
+  * @brief  Verify if active page is full and Writes variable in EEPROM.
+  * @param  Address: 16 bit virtual address of the variable
+  * @param  Data: 16 bit data to be written as variable value
+  * @retval Success or error status:
+  *           - FLASH_COMPLETE: on success
+  *           - EEPROM_PAGE_FULL: if valid page is full (need page transfer)
+  *           - EEPROM_NO_VALID_PAGE: if no valid page was found
+  *           - EEPROM_OUT_SIZE: if EEPROM size exceeded
+  *           - Flash error code: on write Flash error
+  */
+uint16_t EE_VerifyPageFullWriteVariable(uint16_t Address, uint16_t Data)
+{
+    FLASH_Status FlashStatus;
+    uint32_t idx, pageBase, pageEnd, newPage;
+    uint16_t count;
+
+    // Get valid Page for write operation
+    pageBase = EE_FindValidPage();
+    if (pageBase == 0)
+        return  EEPROM_NO_VALID_PAGE;
+
+    // Get the valid Page end Address
+    pageEnd = pageBase + PageSize;          // Set end of page
+
+    for (idx = pageEnd - 2; idx > pageBase; idx -= 4)
+    {
+        if ((*(__IO uint16_t*)idx) == Address)      // Find last value for address
+        {
+            count = (*(__IO uint16_t*)(idx - 2));   // Read last data
+            if (count == Data)
+                return EEPROM_OK;
+            if (count == 0xFFFF)
+            {
+                FlashStatus = FLASH_ProgramHalfWord(idx - 2, Data); // Set variable data
+                if (FlashStatus == FLASH_COMPLETE)
+                    return EEPROM_OK;
+            }
+            break;
+        }
+    }
+
+    // Check each active page address starting from begining
+    for (idx = pageBase + 4; idx < pageEnd; idx += 4)
+        if ((*(__IO uint32_t*)idx) == 0xFFFFFFFF)               // Verify if element 
+        {                                                   //  contents are 0xFFFFFFFF
+            FlashStatus = FLASH_ProgramHalfWord(idx, Data); // Set variable data
+            if (FlashStatus != FLASH_COMPLETE)
+                return FlashStatus;
+            FlashStatus = FLASH_ProgramHalfWord(idx + 2, Address);  // Set variable virtual address
+            if (FlashStatus != FLASH_COMPLETE)
+                return FlashStatus;
+            return EEPROM_OK;
+        }
+
+    // Empty slot not found, need page transfer
+    // Calculate unique variables in page
+    count = EE_GetVariablesCount(pageBase, Address) + 1;
+    if (count >= (PageSize / 4 - 1))
+        return EEPROM_OUT_SIZE;
+
+    if (pageBase == PageBase1)
+        newPage = PageBase0;        // New page address where variable will be moved to
+    else
+        newPage = PageBase1;
+
+    // Set the new Page status to RECEIVE_DATA status
+    FlashStatus = FLASH_ProgramHalfWord(newPage, EEPROM_RECEIVE_DATA);
+    if (FlashStatus != FLASH_COMPLETE)
+        return FlashStatus;
+
+    // Write the variable passed as parameter in the new active page
+    FlashStatus = FLASH_ProgramHalfWord(newPage + 4, Data);
+    if (FlashStatus != FLASH_COMPLETE)
+        return FlashStatus;
+
+    FlashStatus = FLASH_ProgramHalfWord(newPage + 6, Address);
+    if (FlashStatus != FLASH_COMPLETE)
+        return FlashStatus;
+
+    return EE_PageTransfer(newPage, pageBase, Address);
+}
+
+/*EEPROMClass::EEPROMClass(void)
+{
+    PageBase0 = EEPROM_PAGE0_BASE;
+    PageBase1 = EEPROM_PAGE1_BASE;
+    PageSize = EEPROM_PAGE_SIZE;
+    Status = EEPROM_NOT_INIT;
+}*/
+/*
+uint16_t EEPROM_init(uint32_t pageBase0, uint32_t pageBase1, uint32_t pageSize)
+{
+    PageBase0 = pageBase0;
+    PageBase1 = pageBase1;
+    PageSize = pageSize;
+    return EEPROM_init();
+}*/
+
+uint16_t EEPROM_init(void)
+{
+    uint16_t status0 = 6, status1 = 6;
+    FLASH_Status FlashStatus;
+
+    FLASH_Unlock();
+    Status = EEPROM_NO_VALID_PAGE;
+
+    status0 = (*(__IO uint16_t *)PageBase0);
+    status1 = (*(__IO uint16_t *)PageBase1);
+
+    switch (status0)
+    {
+/*
+        Page0               Page1
+        -----               -----
+    EEPROM_ERASED       EEPROM_VALID_PAGE           Page1 valid, Page0 erased
+                        EEPROM_RECEIVE_DATA         Page1 need set to valid, Page0 erased
+                        EEPROM_ERASED               make EE_Format
+                        any                         Error: EEPROM_NO_VALID_PAGE
+*/
+    case EEPROM_ERASED:
+        if (status1 == EEPROM_VALID_PAGE)           // Page0 erased, Page1 valid
+            Status = EE_CheckErasePage(PageBase0, EEPROM_ERASED);
+        else if (status1 == EEPROM_RECEIVE_DATA)    // Page0 erased, Page1 receive
+        {
+            FlashStatus = FLASH_ProgramHalfWord(PageBase1, EEPROM_VALID_PAGE);
+            if (FlashStatus != FLASH_COMPLETE)
+                Status = FlashStatus;
+            else
+                Status = EE_CheckErasePage(PageBase0, EEPROM_ERASED);
+        }
+        else if (status1 == EEPROM_ERASED)          // Both in erased state so format EEPROM
+            Status = EEPROM_format();
+        break;
+/*
+        Page0               Page1
+        -----               -----
+    EEPROM_RECEIVE_DATA EEPROM_VALID_PAGE           Transfer Page1 to Page0
+                        EEPROM_ERASED               Page0 need set to valid, Page1 erased
+                        any                         EEPROM_NO_VALID_PAGE
+*/
+    case EEPROM_RECEIVE_DATA:
+        if (status1 == EEPROM_VALID_PAGE)           // Page0 receive, Page1 valid
+            Status = EE_PageTransfer(PageBase0, PageBase1, 0xFFFF);
+        else if (status1 == EEPROM_ERASED)          // Page0 receive, Page1 erased
+        {
+            Status = EE_CheckErasePage(PageBase1, EEPROM_ERASED);
+            if (Status == EEPROM_OK)
+            {
+                FlashStatus = FLASH_ProgramHalfWord(PageBase0, EEPROM_VALID_PAGE);
+                if (FlashStatus != FLASH_COMPLETE)
+                    Status = FlashStatus;
+                else
+                    Status = EEPROM_OK;
+            }
+        }
+        break;
+/*
+        Page0               Page1
+        -----               -----
+    EEPROM_VALID_PAGE   EEPROM_VALID_PAGE           Error: EEPROM_NO_VALID_PAGE
+                        EEPROM_RECEIVE_DATA         Transfer Page0 to Page1
+                        any                         Page0 valid, Page1 erased
+*/
+    case EEPROM_VALID_PAGE:
+        if (status1 == EEPROM_VALID_PAGE)           // Both pages valid
+            Status = EEPROM_NO_VALID_PAGE;
+        else if (status1 == EEPROM_RECEIVE_DATA)
+            Status = EE_PageTransfer(PageBase1, PageBase0, 0xFFFF);
+        else
+            Status = EE_CheckErasePage(PageBase1, EEPROM_ERASED);
+        break;
+/*
+        Page0               Page1
+        -----               -----
+        any             EEPROM_VALID_PAGE           Page1 valid, Page0 erased
+                        EEPROM_RECEIVE_DATA         Page1 valid, Page0 erased
+                        any                         EEPROM_NO_VALID_PAGE
+*/
+    default:
+        if (status1 == EEPROM_VALID_PAGE)
+            Status = EE_CheckErasePage(PageBase0, EEPROM_ERASED);   // Check/Erase Page0
+        else if (status1 == EEPROM_RECEIVE_DATA)
+        {
+            FlashStatus = FLASH_ProgramHalfWord(PageBase1, EEPROM_VALID_PAGE);
+            if (FlashStatus != FLASH_COMPLETE)
+                Status = FlashStatus;
+            else
+                Status = EE_CheckErasePage(PageBase0, EEPROM_ERASED);
+        }
+        break;
+    }
+    return Status;
+}
+
+/**
+  * @brief  Erases PAGE0 and PAGE1 and writes EEPROM_VALID_PAGE / 0 header to PAGE0
+  * @param  PAGE0 and PAGE1 base addresses
+  * @retval Status of the last operation (Flash write or erase) done during EEPROM formating
+  */
+uint16_t EEPROM_format(void)
+{
+    uint16_t status;
+    FLASH_Status FlashStatus;
+
+    FLASH_Unlock();
+
+    // Erase Page0
+    status = EE_CheckErasePage(PageBase0, EEPROM_VALID_PAGE);
+    if (status != EEPROM_OK)
+        return status;
+    if ((*(__IO uint16_t*)PageBase0) == EEPROM_ERASED)
+    {
+        // Set Page0 as valid page: Write VALID_PAGE at Page0 base address
+        FlashStatus = FLASH_ProgramHalfWord(PageBase0, EEPROM_VALID_PAGE);
+        if (FlashStatus != FLASH_COMPLETE)
+            return FlashStatus;
+    }
+    // Erase Page1
+    return EE_CheckErasePage(PageBase1, EEPROM_ERASED);
+}
+
+/**
+  * @brief  Returns the erase counter for current page
+  * @param  Data: Global variable contains the read variable value
+  * @retval Success or error status:
+  *         - EEPROM_OK: if erases counter return.
+  *         - EEPROM_NO_VALID_PAGE: if no valid page was found.
+  */
+uint16_t EEPROM_erases(uint16_t *Erases)
+{
+    uint32_t pageBase;
+    if (Status != EEPROM_OK)
+        if (EEPROM_init() != EEPROM_OK)
+            return Status;
+
+    // Get active Page for read operation
+    pageBase = EE_FindValidPage();
+    if (pageBase == 0)
+        return  EEPROM_NO_VALID_PAGE;
+
+    *Erases = (*(__IO uint16_t*)pageBase+2);
+    return EEPROM_OK;
+}
+
+/**
+  * @brief  Returns the last stored variable data, if found,
+  *         which correspond to the passed virtual address
+  * @param  Address: Variable virtual address
+  * @retval Data for variable or EEPROM_DEFAULT_DATA, if any errors
+  */
+/*
+uint16_t EEPROM_read (uint16_t Address)
+{
+    uint16_t data;
+    EEPROM_read(Address, &data);
+    return data;
+}*/
+
+/**
+  * @brief  Returns the last stored variable data, if found,
+  *         which correspond to the passed virtual address
+  * @param  Address: Variable virtual address
+  * @param  Data: Pointer to data variable
+  * @retval Success or error status:
+  *           - EEPROM_OK: if variable was found
+  *           - EEPROM_BAD_ADDRESS: if the variable was not found
+  *           - EEPROM_NO_VALID_PAGE: if no valid page was found.
+  */
+uint16_t EEPROM_read(uint16_t Address, uint16_t *Data)
+{
+    uint32_t pageBase, pageEnd;
+
+    // Set default data (empty EEPROM)
+    *Data = EEPROM_DEFAULT_DATA;
+
+    if (Status == EEPROM_NOT_INIT)
+        if (EEPROM_init() != EEPROM_OK)
+            return Status;
+
+    // Get active Page for read operation
+    pageBase = EE_FindValidPage();
+    if (pageBase == 0)
+        return  EEPROM_NO_VALID_PAGE;
+
+    // Get the valid Page end Address
+    pageEnd = pageBase + ((uint32_t)(PageSize - 2));
+    
+    // Check each active page address starting from end
+    for (pageBase += 6; pageEnd >= pageBase; pageEnd -= 4)
+        if ((*(__IO uint16_t*)pageEnd) == Address)      // Compare the read address with the virtual address
+        {
+            *Data = (*(__IO uint16_t*)(pageEnd - 2));       // Get content of Address-2 which is variable value
+            return EEPROM_OK;
+        }
+
+    // Return ReadStatus value: (0: variable exist, 1: variable doesn't exist)
+    return EEPROM_BAD_ADDRESS;
+}
+
+/**
+  * @brief  Writes/upadtes variable data in EEPROM.
+  * @param  VirtAddress: Variable virtual address
+  * @param  Data: 16 bit data to be written
+  * @retval Success or error status:
+  *         - FLASH_COMPLETE: on success
+  *         - EEPROM_BAD_ADDRESS: if address = 0xFFFF
+  *         - EEPROM_PAGE_FULL: if valid page is full
+  *         - EEPROM_NO_VALID_PAGE: if no valid page was found
+  *         - EEPROM_OUT_SIZE: if no empty EEPROM variables
+  *         - Flash error code: on write Flash error
+  */
+uint16_t EEPROM_write(uint16_t Address, uint16_t Data)
+{
+    if (Status == EEPROM_NOT_INIT)
+        if (EEPROM_init() != EEPROM_OK)
+            return Status;
+
+    if (Address == 0xFFFF)
+        return EEPROM_BAD_ADDRESS;
+
+    // Write the variable virtual address and value in the EEPROM
+    uint16_t status = EE_VerifyPageFullWriteVariable(Address, Data);
+    return status;
+}
+
+/**
+  * @brief  Writes/upadtes variable data in EEPROM.
+            The value is written only if differs from the one already saved at the same address.
+  * @param  VirtAddress: Variable virtual address
+  * @param  Data: 16 bit data to be written
+  * @retval Success or error status:
+  *         - EEPROM_SAME_VALUE: If new Data matches existing EEPROM Data
+  *         - FLASH_COMPLETE: on success
+  *         - EEPROM_BAD_ADDRESS: if address = 0xFFFF
+  *         - EEPROM_PAGE_FULL: if valid page is full
+  *         - EEPROM_NO_VALID_PAGE: if no valid page was found
+  *         - EEPROM_OUT_SIZE: if no empty EEPROM variables
+  *         - Flash error code: on write Flash error
+  */
+uint16_t EEPROM_update(uint16_t Address, uint16_t Data)
+{
+    uint16_t temp;
+    EEPROM_read(Address, &temp);
+    if (Address == Data)
+        return EEPROM_SAME_VALUE;
+    else
+        return EEPROM_write(Address, Data);
+}
+
+/**
+  * @brief  Return number of variable
+  * @retval Number of variables
+  */
+uint16_t EEPROM_count(uint16_t *Count)
+{
+    if (Status == EEPROM_NOT_INIT)
+        if (EEPROM_init() != EEPROM_OK)
+            return Status;
+
+    // Get valid Page for write operation
+    uint32_t pageBase = EE_FindValidPage();
+    if (pageBase == 0)
+        return EEPROM_NO_VALID_PAGE;    // No valid page, return max. numbers
+
+    *Count = EE_GetVariablesCount(pageBase, 0xFFFF);
+    return EEPROM_OK;
+}
+
+uint16_t EEPROM_maxcount(void)
+{
+    return ((PageSize / 4)-1);
+}
+
+
+uint8_t eeprom_read_byte (const uint8_t *Address)
+{
+    const uint16_t p = (const uint32_t) Address;
+    uint16_t temp;
+    EEPROM_read(p, &temp);
+    return (uint8_t) temp;
+}
+
+void eeprom_write_byte (uint8_t *Address, uint8_t Value)
+{
+    uint16_t p = (uint32_t) Address;
+    EEPROM_write(p, (uint16_t) Value);
+}
+
+void eeprom_update_byte (uint8_t *Address, uint8_t Value)
+{
+    uint16_t p = (uint32_t) Address;
+    EEPROM_update(p, (uint16_t) Value);
+}
+
+uint16_t eeprom_read_word (const uint16_t *Address)
+{
+    const uint16_t p = (const uint32_t) Address;
+    uint16_t temp;
+    EEPROM_read(p, &temp);
+    return temp;
+}
+
+void eeprom_write_word (uint16_t *Address, uint16_t Value)
+{
+    uint16_t p = (uint32_t) Address;
+    EEPROM_write(p, Value);
+}
+
+void eeprom_update_word (uint16_t *Address, uint16_t Value)
+{
+    uint16_t p = (uint32_t) Address;
+    EEPROM_update(p, Value);
+}
+
+uint32_t eeprom_read_dword (const uint32_t *Address)
+{
+    const uint16_t p = (const uint32_t) Address;
+    uint16_t temp1, temp2;
+    EEPROM_read(p, &temp1);
+    EEPROM_read(p + 1, &temp2);
+    return temp1 | (temp2 << 16);
+}
+
+void eeprom_write_dword (uint32_t *Address, uint32_t Value)
+{
+    uint16_t temp = (uint16_t) Value;
+    uint16_t p = (uint32_t) Address;
+    EEPROM_write(p, temp);
+    temp = (uint16_t) (Value >> 16);
+    EEPROM_write(p + 1, temp);
+}
+
+void eeprom_update_dword (uint32_t *Address, uint32_t Value)
+{
+    uint16_t temp = (uint16_t) Value;
+    uint16_t p = (uint32_t) Address;
+    EEPROM_update(p, temp);
+    temp = (uint16_t) (Value >> 16);
+    EEPROM_update(p + 1, temp);
+}
diff --git a/tmk_core/common/chibios/eeprom_stm32.h b/tmk_core/common/chibios/eeprom_stm32.h
new file mode 100755
index 0000000000..d06d302665
--- /dev/null
+++ b/tmk_core/common/chibios/eeprom_stm32.h
@@ -0,0 +1,89 @@
+/*
+ * This software is experimental and a work in progress.
+ * Under no circumstances should these files be used in relation to any critical system(s).
+ * Use of these files is at your own risk.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and 
+ * https://github.com/leaflabs/libmaple
+ *
+ * Modifications for QMK and STM32F303 by Yiancar
+ */
+
+// This file must be modified if the MCU is not defined below.
+// This library also assumes that the pages are not used by the firmware.
+
+#ifndef __EEPROM_H
+#define __EEPROM_H
+
+#include "ch.h"
+#include "hal.h"
+#include "flash_stm32.h"
+
+// HACK ALERT. This definition may not match your processor
+// To Do. Work out correct value for EEPROM_PAGE_SIZE on the STM32F103CT6 etc 
+#define MCU_STM32F303CC
+
+#ifndef EEPROM_PAGE_SIZE
+    #if defined (MCU_STM32F103RB)
+        #define EEPROM_PAGE_SIZE    (uint16_t)0x400  /* Page size = 1KByte */
+    #elif defined (MCU_STM32F103ZE) || defined (MCU_STM32F103RE) || defined (MCU_STM32F103RD) || defined (MCU_STM32F303CC)
+        #define EEPROM_PAGE_SIZE    (uint16_t)0x800  /* Page size = 2KByte */
+    #else
+        #error  "No MCU type specified. Add something like -DMCU_STM32F103RB to your compiler arguments (probably in a Makefile)."
+    #endif
+#endif
+
+#ifndef EEPROM_START_ADDRESS
+    #if defined (MCU_STM32F103RB)
+        #define EEPROM_START_ADDRESS    ((uint32_t)(0x8000000 + 128 * 1024 - 2 * EEPROM_PAGE_SIZE))
+    #elif defined (MCU_STM32F103ZE) || defined (MCU_STM32F103RE)
+        #define EEPROM_START_ADDRESS    ((uint32_t)(0x8000000 + 512 * 1024 - 2 * EEPROM_PAGE_SIZE))
+    #elif defined (MCU_STM32F103RD)
+        #define EEPROM_START_ADDRESS    ((uint32_t)(0x8000000 + 384 * 1024 - 2 * EEPROM_PAGE_SIZE))
+    #elif defined (MCU_STM32F303CC)
+        #define EEPROM_START_ADDRESS    ((uint32_t)(0x8000000 + 250 * 1024 - 2 * EEPROM_PAGE_SIZE))
+    #else
+        #error  "No MCU type specified. Add something like -DMCU_STM32F103RB to your compiler arguments (probably in a Makefile)."
+    #endif
+#endif
+
+/* Pages 0 and 1 base and end addresses */
+#define EEPROM_PAGE0_BASE       ((uint32_t)(EEPROM_START_ADDRESS + 0x000))
+#define EEPROM_PAGE1_BASE       ((uint32_t)(EEPROM_START_ADDRESS + EEPROM_PAGE_SIZE))
+
+/* Page status definitions */
+#define EEPROM_ERASED           ((uint16_t)0xFFFF)  /* PAGE is empty */
+#define EEPROM_RECEIVE_DATA     ((uint16_t)0xEEEE)  /* PAGE is marked to receive data */
+#define EEPROM_VALID_PAGE       ((uint16_t)0x0000)  /* PAGE containing valid data */
+
+/* Page full define */
+enum uint16_t
+    {
+    EEPROM_OK               = ((uint16_t)0x0000),
+    EEPROM_OUT_SIZE         = ((uint16_t)0x0081),
+    EEPROM_BAD_ADDRESS      = ((uint16_t)0x0082),
+    EEPROM_BAD_FLASH        = ((uint16_t)0x0083),
+    EEPROM_NOT_INIT         = ((uint16_t)0x0084),
+    EEPROM_SAME_VALUE       = ((uint16_t)0x0085),
+    EEPROM_NO_VALID_PAGE    = ((uint16_t)0x00AB)
+    };
+
+#define EEPROM_DEFAULT_DATA     0xFFFF
+
+    uint16_t EEPROM_init(void);
+    uint16_t EEPROM_format(void);
+    uint16_t EEPROM_erases(uint16_t *);
+    uint16_t EEPROM_read (uint16_t address, uint16_t *data);
+    uint16_t EEPROM_write(uint16_t address, uint16_t data);
+    uint16_t EEPROM_update(uint16_t address, uint16_t data);
+    uint16_t EEPROM_count(uint16_t *);
+    uint16_t EEPROM_maxcount(void);
+
+#endif  /* __EEPROM_H */
diff --git a/tmk_core/common/chibios/eeprom.c b/tmk_core/common/chibios/eeprom_teensy.c
index 9061b790c4..9061b790c4 100644
--- a/tmk_core/common/chibios/eeprom.c
+++ b/tmk_core/common/chibios/eeprom_teensy.c
diff --git a/tmk_core/common/chibios/flash_stm32.c b/tmk_core/common/chibios/flash_stm32.c
new file mode 100755
index 0000000000..e7199ac7b1
--- /dev/null
+++ b/tmk_core/common/chibios/flash_stm32.c
@@ -0,0 +1,180 @@
+/*
+ * This software is experimental and a work in progress.
+ * Under no circumstances should these files be used in relation to any critical system(s).
+ * Use of these files is at your own risk.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and 
+ * https://github.com/leaflabs/libmaple
+ *
+ * Modifications for QMK and STM32F303 by Yiancar
+ */
+
+#define STM32F303xC
+
+#include "stm32f3xx.h"
+#include "flash_stm32.h"
+
+#define FLASH_KEY1          ((uint32_t)0x45670123)
+#define FLASH_KEY2          ((uint32_t)0xCDEF89AB)
+
+/* Delay definition */
+#define EraseTimeout        ((uint32_t)0x00000FFF)
+#define ProgramTimeout      ((uint32_t)0x0000001F)
+
+#define ASSERT(exp) (void)((0))
+
+/**
+  * @brief  Inserts a time delay.
+  * @param  None
+  * @retval None
+  */
+static void delay(void)
+{
+    __IO uint32_t i = 0;
+    for(i = 0xFF; i != 0; i--) { }
+}
+
+/**
+  * @brief  Returns the FLASH Status.
+  * @param  None
+  * @retval FLASH Status: The returned value can be: FLASH_BUSY, FLASH_ERROR_PG,
+  *   FLASH_ERROR_WRP or FLASH_COMPLETE
+  */
+FLASH_Status FLASH_GetStatus(void)
+{
+    if ((FLASH->SR & FLASH_SR_BSY) == FLASH_SR_BSY)
+        return FLASH_BUSY;
+
+    if ((FLASH->SR & FLASH_SR_PGERR) != 0)
+        return FLASH_ERROR_PG;
+
+    if ((FLASH->SR & FLASH_SR_WRPERR) != 0 )
+        return FLASH_ERROR_WRP;
+
+    if ((FLASH->SR & FLASH_OBR_OPTERR) != 0 )
+        return FLASH_ERROR_OPT;
+
+    return FLASH_COMPLETE;
+}
+
+/**
+  * @brief  Waits for a Flash operation to complete or a TIMEOUT to occur.
+  * @param  Timeout: FLASH progamming Timeout
+  * @retval FLASH Status: The returned value can be: FLASH_ERROR_PG,
+  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT.
+  */
+FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout)
+{ 
+    FLASH_Status status;
+
+    /* Check for the Flash Status */
+    status = FLASH_GetStatus();
+    /* Wait for a Flash operation to complete or a TIMEOUT to occur */
+    while ((status == FLASH_BUSY) && (Timeout != 0x00))
+    {
+        delay();
+        status = FLASH_GetStatus();
+        Timeout--;
+    }
+    if (Timeout == 0)
+        status = FLASH_TIMEOUT;
+    /* Return the operation status */
+    return status;
+}
+
+/**
+  * @brief  Erases a specified FLASH page.
+  * @param  Page_Address: The page address to be erased.
+  * @retval FLASH Status: The returned value can be: FLASH_BUSY, FLASH_ERROR_PG,
+  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT.
+  */
+FLASH_Status FLASH_ErasePage(uint32_t Page_Address)
+{
+    FLASH_Status status = FLASH_COMPLETE;
+    /* Check the parameters */
+    ASSERT(IS_FLASH_ADDRESS(Page_Address));
+    /* Wait for last operation to be completed */
+    status = FLASH_WaitForLastOperation(EraseTimeout);
+  
+    if(status == FLASH_COMPLETE)
+    {
+        /* if the previous operation is completed, proceed to erase the page */
+        FLASH->CR |= FLASH_CR_PER;
+        FLASH->AR = Page_Address;
+        FLASH->CR |= FLASH_CR_STRT;
+
+        /* Wait for last operation to be completed */
+        status = FLASH_WaitForLastOperation(EraseTimeout);
+        if(status != FLASH_TIMEOUT)
+        {
+            /* if the erase operation is completed, disable the PER Bit */
+            FLASH->CR &= ~FLASH_CR_PER;
+        }
+        FLASH->SR = (FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPERR);
+    }
+    /* Return the Erase Status */
+    return status;
+}
+
+/**
+  * @brief  Programs a half word at a specified address.
+  * @param  Address: specifies the address to be programmed.
+  * @param  Data: specifies the data to be programmed.
+  * @retval FLASH Status: The returned value can be: FLASH_ERROR_PG,
+  *   FLASH_ERROR_WRP, FLASH_COMPLETE or FLASH_TIMEOUT. 
+  */
+FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data)
+{
+    FLASH_Status status = FLASH_BAD_ADDRESS;
+
+    if (IS_FLASH_ADDRESS(Address))
+    {
+        /* Wait for last operation to be completed */
+        status = FLASH_WaitForLastOperation(ProgramTimeout);
+        if(status == FLASH_COMPLETE)
+        {
+            /* if the previous operation is completed, proceed to program the new data */
+            FLASH->CR |= FLASH_CR_PG;
+            *(__IO uint16_t*)Address = Data;
+            /* Wait for last operation to be completed */
+            status = FLASH_WaitForLastOperation(ProgramTimeout);
+            if(status != FLASH_TIMEOUT)
+            {
+                /* if the program operation is completed, disable the PG Bit */
+                FLASH->CR &= ~FLASH_CR_PG;
+            }
+            FLASH->SR = (FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPERR);
+        }
+    }
+    return status;
+}
+
+/**
+  * @brief  Unlocks the FLASH Program Erase Controller.
+  * @param  None
+  * @retval None
+  */
+void FLASH_Unlock(void)
+{
+    /* Authorize the FPEC Access */
+    FLASH->KEYR = FLASH_KEY1;
+    FLASH->KEYR = FLASH_KEY2;
+}
+
+/**
+  * @brief  Locks the FLASH Program Erase Controller.
+  * @param  None
+  * @retval None
+  */
+void FLASH_Lock(void)
+{
+    /* Set the Lock Bit to lock the FPEC and the FCR */
+    FLASH->CR |= FLASH_CR_LOCK;
+}
diff --git a/tmk_core/common/chibios/flash_stm32.h b/tmk_core/common/chibios/flash_stm32.h
new file mode 100755
index 0000000000..cc065cbca2
--- /dev/null
+++ b/tmk_core/common/chibios/flash_stm32.h
@@ -0,0 +1,53 @@
+/*
+ * This software is experimental and a work in progress.
+ * Under no circumstances should these files be used in relation to any critical system(s).
+ * Use of these files is at your own risk.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * This files are free to use from https://github.com/rogerclarkmelbourne/Arduino_STM32 and 
+ * https://github.com/leaflabs/libmaple
+ *
+ * Modifications for QMK and STM32F303 by Yiancar
+ */
+
+#ifndef __FLASH_STM32_H
+#define __FLASH_STM32_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+#include "ch.h"
+#include "hal.h"
+
+typedef enum
+    {
+    FLASH_BUSY = 1,
+    FLASH_ERROR_PG,
+    FLASH_ERROR_WRP,
+    FLASH_ERROR_OPT,
+    FLASH_COMPLETE,
+    FLASH_TIMEOUT,
+    FLASH_BAD_ADDRESS
+    } FLASH_Status;
+
+#define IS_FLASH_ADDRESS(ADDRESS) (((ADDRESS) >= 0x08000000) && ((ADDRESS) < 0x0807FFFF))
+
+FLASH_Status FLASH_WaitForLastOperation(uint32_t Timeout);
+FLASH_Status FLASH_ErasePage(uint32_t Page_Address);
+FLASH_Status FLASH_ProgramHalfWord(uint32_t Address, uint16_t Data);
+
+void FLASH_Unlock(void);
+void FLASH_Lock(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __FLASH_STM32_H */
diff --git a/tmk_core/common/eeconfig.c b/tmk_core/common/eeconfig.c
index 3e5987ee3b..35de574a96 100644
--- a/tmk_core/common/eeconfig.c
+++ b/tmk_core/common/eeconfig.c
@@ -3,12 +3,20 @@
 #include "eeprom.h"
 #include "eeconfig.h"
 
+#ifdef STM32F303xC
+#include "hal.h"
+#include "eeprom_stm32.h"
+#endif
+
 /** \brief eeconfig initialization
  *
  * FIXME: needs doc
  */
 void eeconfig_init(void)
 {
+#ifdef STM32F303xC
+    EEPROM_format();
+#endif
     eeprom_update_word(EECONFIG_MAGIC,          EECONFIG_MAGIC_NUMBER);
     eeprom_update_byte(EECONFIG_DEBUG,          0);
     eeprom_update_byte(EECONFIG_DEFAULT_LAYER,  0);
@@ -43,6 +51,9 @@ void eeconfig_enable(void)
  */
 void eeconfig_disable(void)
 {
+#ifdef STM32F303xC
+    EEPROM_format();
+#endif
     eeprom_update_word(EECONFIG_MAGIC, 0xFFFF);
 }
 
diff --git a/tmk_core/common/eeconfig.h b/tmk_core/common/eeconfig.h
index 1397a90c79..fa498df48c 100644
--- a/tmk_core/common/eeconfig.h
+++ b/tmk_core/common/eeconfig.h
@@ -25,6 +25,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define EECONFIG_MAGIC_NUMBER                       (uint16_t)0xFEED
 
 /* eeprom parameteter address */
+#if !defined(STM32F303xC)
 #define EECONFIG_MAGIC                              (uint16_t *)0
 #define EECONFIG_DEBUG                              (uint8_t *)2
 #define EECONFIG_DEFAULT_LAYER                      (uint8_t *)3
@@ -38,6 +39,21 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // EEHANDS for two handed boards
 #define EECONFIG_HANDEDNESS         				(uint8_t *)14
 
+#else
+/* STM32F3 uses 16byte block. Reconfigure memory map */
+#define EECONFIG_MAGIC                              (uint16_t *)0
+#define EECONFIG_DEBUG                              (uint8_t *)1
+#define EECONFIG_DEFAULT_LAYER                      (uint8_t *)2
+#define EECONFIG_KEYMAP                             (uint8_t *)3
+#define EECONFIG_MOUSEKEY_ACCEL                     (uint8_t *)4
+#define EECONFIG_BACKLIGHT                          (uint8_t *)5
+#define EECONFIG_AUDIO                              (uint8_t *)6
+#define EECONFIG_RGBLIGHT                           (uint32_t *)7
+#define EECONFIG_UNICODEMODE                        (uint8_t *)9
+#define EECONFIG_STENOMODE                          (uint8_t *)10
+// EEHANDS for two handed boards
+#define EECONFIG_HANDEDNESS         				(uint8_t *)11
+#endif
 
 /* debug bit */
 #define EECONFIG_DEBUG_ENABLE                       (1<<0)
diff --git a/tmk_core/protocol/chibios/main.c b/tmk_core/protocol/chibios/main.c
index f2abc438d4..568c1edb28 100644
--- a/tmk_core/protocol/chibios/main.c
+++ b/tmk_core/protocol/chibios/main.c
@@ -44,6 +44,9 @@
 #ifdef MIDI_ENABLE
 #include "qmk_midi.h"
 #endif
+#ifdef STM32F303xC
+#include "eeprom_stm32.h"
+#endif
 #include "suspend.h"
 #include "wait.h"
 
@@ -109,6 +112,10 @@ int main(void) {
   halInit();
   chSysInit();
 
+#ifdef STM32F303xC
+  EEPROM_init();
+#endif
+
   // TESTING
   // chThdCreateStatic(waThread1, sizeof(waThread1), NORMALPRIO, Thread1, NULL);