This application note describes an EEPROM emulation technique using the on-chip Flash memory in the STM32F10x devices. It also discusses the differences between external EEPROM and embedded Flash memory.
This document explains the differences between external EEPROM and embedded Flash memory, focusing on write access time, writing method, and erase time. It details how STM32F10x devices, which do not include physical EEPROM, can emulate this functionality using on-chip Flash memory.
The note outlines the principle of EEPROM emulation using two Flash memory pages, describing the header status switching and data update flows. It also covers embedded application aspects such as data granularity management, wear leveling to improve Flash endurance, and page header recovery in the event of power loss.
| Low-density devices Flash memory density | 16 to 32 Kbytes |
|---|---|
| Medium-density devices Flash memory density | 32 to 128 Kbytes |
| High-density devices Flash memory density | 256 to 512 Kbytes |
| Connectivity line devices | STM32F105xx and STM32F107xx |
External EEPROM has a write access time of 5 to 10 ms for random bytes, whereas emulated EEPROM using Flash memory has a write access time of 20 us for a word.
Yes, unlike standalone external EEPROM, the write process for emulated EEPROM using embedded Flash memory can be interrupted by a CPU reset.
The document references a table for this specific limit but does not provide the exact number in the text provided.