fix bugs in STM32G4 settings storage

Author: Richard Unger

src/settings/README.md

@@ -19,8 +19,8 @@ Supported hardware:
 Some SAMD chips have a built-in NVRAM flash, which can be written from user code.
 - [CAT24 I2C Flash EEPROMs](i2c/) :warning: UNFINISHED \
 Simple programmable memories with I2C interface. Memory space is quite limited, but enough for storing settings.
-- [STM32 Flash](stm32/) :warning: UNFINISHED \
-Store settings directly to STM32 on-board flash
+- [STM32G4 Flash](stm32/) \
+Store settings directly to STM32G4 MCU's on-board flash.
 
 See Roadmap, below, for systems we may support in the future.
 

src/settings/stm32/README.md

@@ -12,6 +12,14 @@ of space, maximum. If you need more space than this, you can provide the start a
 
 Needless to say, you can only store settings to flash if that memory is not also needed by your program. So you have to have some reserve space in the flash of the MCU you're using. If memory is too tight, use a STM32 model with more flash.
 
+## Compatibility
+
+Currently only **STM32G4** MCUs are supported.
+
+G4s are nice MCUs for using the flash because the page size is 2kB and you can erase the flash page by page. For this reason the default settings use the last page of flash as the storage location, leaving all the rest of the flash for your code and data. Pages are 2kB in size, which should be more than enough for most setups.
+
+Note: systems with dual bank flash have not been tested, and will probably not work.
+
 ## Board setup
 
 When storing settings to the Flash of your STM32 MCU, you have to consider what happens when you reprogram the MCU. Unless you have taken steps in the board setup files to reserve the pages of flash used by the settings, they will generally be erased and/or overwritten when programming the MCU.

src/settings/stm32/STM32FlashSettingsStorage.cpp

@@ -2,7 +2,7 @@
 
 #include "./STM32FlashSettingsStorage.h"
 
-#if defined(_STM32_DEF_)
+#if defined(STM32G4xx)
 
 #include "communication/SimpleFOCDebug.h"
 
@@ -38,23 +38,25 @@ void STM32FlashSettingsStorage::beforeSave(){
     _page = PAGE_OF(_writeptr);
     if (HAL_FLASH_Unlock()!=HAL_OK)
         SimpleFOCDebug::println("SS: Flash unlock err");
-    delay(50);
+    __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_OPTVERR);
     erasePage(_page);
-    delay(50);
 };
 
 
 void STM32FlashSettingsStorage::erasePage(uint32_t page) {
     FLASH_EraseInitTypeDef eraseInit;    
     eraseInit.TypeErase = FLASH_TYPEERASE_PAGES;
     eraseInit.Page = page;
-    eraseInit.Banks = _bank;
+    eraseInit.Banks = 0;//_bank;
     eraseInit.NbPages = 1;
     uint32_t err;
     SimpleFOCDebug::print("SS: erase page ");
     SimpleFOCDebug::println((int)page);
+    __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_ALL_ERRORS);
     if (HAL_FLASHEx_Erase(&eraseInit, &err) != HAL_OK) {
-        SimpleFOCDebug::println("SS: flash erase err");
+        uint32_t ferr = HAL_FLASH_GetError();
+        SimpleFOCDebug::print("SS: flash erase err nr ");
+        SimpleFOCDebug::println((int)ferr);
         HAL_FLASH_Lock();
         return;
     }
@@ -67,8 +69,12 @@ void STM32FlashSettingsStorage::flushBuffer() {
         erasePage(page);
         _page = page;
     }
-    if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_DOUBLEWORD, (uint32_t)_writeptr, _writeBuffer.l)!=HAL_OK)
-        SimpleFOCDebug::println("SS: Flash write err");
+    __HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_ALL_ERRORS);
+    if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_DOUBLEWORD, (uint32_t)_writeptr, _writeBuffer.l)!=HAL_OK) {
+        uint32_t ferr = HAL_FLASH_GetError();
+        SimpleFOCDebug::println("SS: flash write err nr ");
+        SimpleFOCDebug::println((int)ferr);
+    }
     _writeptr += 8;
     _buffed = 0;
     _writeBuffer.l = 0;

src/settings/stm32/STM32FlashSettingsStorage.h

@@ -3,7 +3,7 @@
 
 #include "../SettingsStorage.h"
 
-#if defined(_STM32_DEF_)
+#if defined(STM32G4xx)
 
 #define PAGE_OF(x) (((uint32_t)x - FLASH_BASE) / FLASH_PAGE_SIZE)
 
@@ -15,8 +15,8 @@ class STM32FlashSettingsStorage : public SettingsStorage {
 
     void init() override;
 
-    uint32_t _bank = FLASH_BANK_1;
-    
+    uint32_t _bank = FLASH_BANK_1; // TODO also support bank 2
+
 protected:
     uint8_t readByte(uint8_t* valueToSet) override;
     uint8_t readFloat(float* valueToSet) override;
@@ -41,7 +41,7 @@ class STM32FlashSettingsStorage : public SettingsStorage {
     uint8_t* _writeptr;
     uint8_t _buffed = 0;
     uint32_t _page = 0;
-    union {
+    __attribute__((aligned(8))) union {
         uint8_t b[8];
         uint64_t l;
     }  _writeBuffer;    // 64-bit buffer