This document explains the differences between external EEPROMs and embedded-Flash, and provides advice on how to substitute external EEPROMs with emulated-EEPROM using the on-chip Flash of ST10F2xx devices. The document assumes that the reader is familiar with handling embedded aspects, focusing on the differences between EEPROMs and embedded-Flash.
The document describes a method for emulating an external EEPROM using the embedded Flash memory found in STMicroelectronics ST10F2xx microcontrollers. It highlights that while the concept is straightforward, specific embedded aspects must be considered to ensure data security and system robustness.
Key differences between standard serial EEPROMs and Flash-based emulation are detailed, including write access times (milliseconds for EEPROM versus microseconds for Flash), writing methods (CPU-independent vs CPU-dependent), and erase times. The text emphasizes that Flash requires block erasure before programming, unlike EEPROM which allows random byte writes.
| Supported Devices | ST10F269, ST10F280, ST10F276, ST10F252, ST10F296 and derivatives |
|---|---|
| EEPROM Erase Time | seconds (ex: 1.58s) |
Yes, unlike EEPROM which allows random byte writes, Flash requires a block erase operation to free up space before write.
Yes, once started by the CPU, the writing can be interrupted by a power failure and by a CPU reset.
No, unlike Flash, EEPROM does not require a block erase operation to free-up space before write.
The content after the interrupt shall be regarded as a totally random content.