RM0367 Rev 7 87/1043
RM0367 Flash program memory and data EEPROM (FLASH)
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This operation aims at writing a word in the Option bytes area. The Option bytes area
can only be written in Level 0 or Level 1.
The user must consider that, in a word, the 16 higher bits (from 16 to 31) have to be the
complement of the 16 lower bits (from 0 to 15): a mismatch between the higher and
lower parts of data would generate an error during the Option bytes loading (see
Section 3.8: Option bytes) and force the memory interface to load the default values.
The memory interface does not check at the write time if the data is correctly
complemented. The user must write the desired value at the right address with a word
size.
As for data EEPROM, the memory interface deletes the previous content before
writing, if necessary. If the data to write is at 0, the memory interface does not execute
the useless write operation. When only a write operation or only an erase operation is
executed, the duration is Tprog (3.2 ms). If both are executed, the duration is 2 x Tprog
(6.4 ms). The memory interface can be forced to execute every time both erase and
write operations set the FIX flag to 1.
Some configurations need a closer attention because they change the protections. The
memory interface can change the Option bytes write in a Mass Erase or force some
bits not to reduce the protections: for more details, see Section 3.4.4: Write/erase
protection management.
• Duration
Tprog (3.2 ms) or 2 x Tprog (6.4 ms).
• Options
FIX bit can be set to force the memory interface to execute every time an erase (to
delete the old content) and a write operation (to write the new data) occur. This gives a
fix time to program for every data value and for previous data.
For code example, refer to A.3.7: Program Option byte code example.
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