MYXX28HC256 Datasheet, PDF (8/23 Pages) Micross Components – No External High Voltages or VPP

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256Kb EEPROM
MYXX28HC256
Resetting Software Data Protection
Figure 10 - Reset Software Data Protection Timing Sequence
V_VCCCC
DATA
ADADTRAESS
ADDRESS
AA
555A5A
5555
CE#
CE#
WE#
WE#
55
2AA5A5
2AAA
80
555580
5555
AA
55
20
5555AA 2AAA55 5555 20
5555
2AAA
5555
tWC _tWC
STANDARD
OPERSATTAINNGDARD
MODEOPERATING
MODE
Figure 11 - Write Sequence for Resetting Software Data Protection
WRITE DATA AA
T_WO_RA_I5DT5DE5R5DE_AS_TS_{A AA}
TO ADDRESS
5555
WRITE DATA 55
TO ADDRESS
WR₂IT_AE_AADATA 55
TO ADDRESS
2AAA
WRITE DATA 80
TO ADDRESS
WR5IT5E55DATA 80
TO ADDRESS
5555
WRITE DATA AA
TO ADDRESS
WRI⁵T⁵E⁵⁵DATA AA
TO ADDRESS
5555
WRITE DATA 55
TO ADDRESS
WR²IT^AE^AADATA 55
TO ADDRESS
2AAA
WRITE DATA 20
TO ADDRESS
5555
WRITE DATA 20
TO ADDRESS
AFTER⁵⁵tW⁵⁵_C,
RE-ENTERS
UNPROTECTED
ASFTTAETRE tWC,
RE-ENTERS
UNPROTECTED
STATE
In the event the user wants to deactivate the software data
protection feature for testing or reprogramming in an EEPROM
programmer, the following six step algorithm will reset the internal
protection circuit. After t_WC, the MYXX28HC256 will be in standard
operating mode.
Note: Once initiated, the sequence of write operations should not
be interrupted.
MYXX28HC256
Revision 1.4 - 02/13
8