ST92F120R1Q7 View Datasheet(PDF) - STMicroelectronics
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Description
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ST92F120R1Q7 Datasheet PDF : 324 Pages
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ST92F120 - SINGLE VOLTAGE FLASH & EEPROM
EEPROM (Cont’d)
3.5.2 EEPROM Update Operation
The update of the EEPROM content can be made
by pages of 16 consecutive bytes. The Page Up-
date operation allows up to 16 bytes to be loaded
into the RAM buffer that replace the ones already
contained in the specified address.
Each time a Page Update operation is executed in
the EEPROM, the RAM buffer content is pro-
grammed in the next free block relative to the
specified page (the RAM buffer is previously auto-
matically filled with old data for all the page ad-
dresses not selected for updating). If all the 4
blocks of the specified page in the current EEP-
ROM sector are full, the page content is copied to
the complementary sector, that becomes the new
current one.
After that the specified page has been copied to
the next free block, one erase phase is executed
Figure 24. Hardware Emulation Flow
on the complementary sector, if the 4 erase phas-
es have not yet been executed. When the selected
page is copied to the complementary sector, the
remaining 63 pages are also copied to the first
block of the new sector; then the first erase phase
is executed on the previous full sector. All this is
executed in a hidden manner, and the End Page
Update Interrupt is generated only after the end of
the complete operation.
At Reset the two status pages are read in order to
detect which is the sector that is currently mapping
the EEPROM, and in which block each page is
mapped. A system defined routine written in Test-
Flash is executed at reset, so that any previously
aborted write operation is restarted and complet-
ed.
Emulation Flow
Reset
Read Status Pages
Map EEPROM
in current sector
Write operation
to complete ?
No
Yes
Complete
Write operation
Update
Status page
Wait for
Update commands
Page
Update
Command
Program selected
Page from RAM buffer
in next free block
new
sector ?
No
Yes
Copy all other Pages
into RAM buffer;
then program them
in next free block
Complementary Yes
sector erased ?
No
1/4 erase of
complementary sector
Update
Status Page
End Page
Update
Interrupt
(to Core)
49/324
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