Hi Wayne
EEProm and flash both require a clear cycle which sets all the bits high. Once cleared, the data can then be written to the device. Not all devices require a high voltage for the erase - Most are rated for 5V... However, the recommended voltages do need to be adhered to, as do the timings of the erase & write strobes.
If the erase timings are too short, data persistence is a problem, likewise, if the write timings are short, data integrity can not be guaranteed.
Regards, Paul.
On Friday 12 November 2004 18:48, Wayne Stallwood wrote:
Original data is written (with a strong write) New Data is written over original data or Original data is deleted (with a weaker write)
Now there remains a ghost of the original data, the memory controller then gets confused and only sees the Original (more persistent ) data.