mbed_controller / storage_on_flash

Tiny storage(file) system on MCU internal flash memory for Nucleo F4xx. The purpose of SOFBlock class is to provide a way to write data on flash memory in the same way of file handling class in the file system.

Dependents:   storage_on_flash_demo mbed_controller_demo mbed-os-example-blinky-2

March 26, 2015

Seeed Arch Max platform which is based on STM32-F407 is supported.

Diff: SOFBlock.h

Revision:
3:2bb58064d0a2
Parent:
2:e79a9cb05801
--- a/SOFBlock.h	Wed Mar 25 05:27:59 2015 +0000
+++ b/SOFBlock.h	Wed Mar 25 05:46:25 2015 +0000
@@ -25,7 +25,7 @@
  *    The base physical address of STM32 flash is 0x08000000.
  *
  * There may be inefficiency in this flash usage scenario when size of data is too small compared with sector size.
- * The size of sectors from #5 to #7 of STM32 401RE Flash 128KB. For example, if I only need to maintain 1KB data,
+ * The size of sectors from #5 to #7 of STM32-F4xx Flash is 128KB. For example, if I only need to maintain 1KB data,
  * whenever I need to update data I need to erase whole 128KB of sector.
  * This produces two problems.
  * One is time consumption of the erase operation. The operation of ERASE128KB takes 1~4 seconds long.
@@ -33,9 +33,11 @@
  * More you erase and write and lifetime of flash is shorter.
  *
  * To overcome such problems, here simple flash management algorithm is used for.
- * By tracking data offset and size it can hold multiple data in a sector. Bear in mind that is impossible rewriting data on Flash.
- * Keeping tracking data along with data itself is crucial without frequent erase operation.
- * To do this, data itself is growing from low address. On the other hand tracking data is growing down from high address.
+ * By tracking data offset and size it can hold multiple data in a sector.
+ * Bear in mind that is impossible rewriting data on Flash.
+ * Keeping tracking data along with data itself without frequent erase operation is crucial.
+ * To do this, data itself is growing from low address.
+ * On the other hand tracking data is growing down from high address.
  * Let's assume the size of data is 1KB and store it in sector #6 which address range is from 0x08040000 to 0x0805ffff.
  * +-------------+----------------------------------------------------------------------+-----+
  * <data>                                                                        <tracking data>
@@ -78,10 +80,10 @@
  * 	// "First Data" printed
  * 	reader.close();
  *
- * SOF_Statics_t statics;
- * if (!SOFBlock(sector_index, statics) || statics.free_size < 11) { // check available byte
+ *  SOF_Statics_t statics;
+ *  if (!SOFBlock(sector_index, statics) || statics.free_size < 11) { // check available byte
  *     SOFBlock::format(sector_index);
- * }
+ *  }
  * 	writer.open(sector_index);
  * 	// Overwrite previous data without erasing flash.
  * 	writer.write_data((uint8_t*)"Second Data", 11);