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EMULATED DATA EEPROM WITH ST7 HDFLASH MEMORY

Figure 2. HDFlash Emulated Data EEPROM (value in 00h..FFh)

2 RESTRICTIONS

s

Only a few data EEPROM bytes with a limited number of write/erase cycles can be emulated

(these characteristics are directly linked to the needed memory space in HDFlash)

s

Emulated data EEPROM must be located in sector 1 or 2 as sector 0 is write protected in

USER mode.

– To use the Embedded Commands the RASS protection must be disabled. So the protec-

tion against unintentional access to the HDFlash control register is no longer available. Un-

intentional programming is only guaranteed by the low probability of accidentally executing

3 ADVANTAGE

s

The HDFlash emulated data EEPROM method can keep the data byte value history.

...

FFh

initial value

FFh

...

00h

valm

...

ptr

ptr

current value

current value

INITIAL STATE

⇒

⇒

FFh

00h

val1

FFh

FFh

FFh

FFh

FFh

FFh

FFh

FFh

00h

val2

00h

val1