HN58V256A Datasheet, PDF (19/25 Pages) Hitachi Semiconductor – 256k EEPROM (32-kword x 8-bit) Ready/Busy and RES function (HN58V257A)

HN58V256A Series, HN58V257A Series
3. Software data protection
To prevent unintentional programming, this device has the software data protection (SDP) mode. The
SDP is enabled by inputting the following 3 bytes code and write data. SDP is not enabled if only the 3
bytes code is input. To program data in the SDP enable mode, 3 bytes code must be input before write
data.
Address
Data
5555
AA
↓
↓
2AAA
55
↓
↓
5555
A0
↓
↓
Write address Write data } Normal data input
The SDP mode is disabled by inputting the following 6 bytes code. Note that, if data is input in the SDP
disable cycle, data can not be written.
Address
5555
↓
2AAA
↓
5555
↓
5555
↓
2AAA
↓
5555
Data
AA
↓
55
↓
80
↓
AA
↓
55
↓
20
The software data protection is not enabled at the shipment.
Note: There are some differences between Renesas Technology’s and other company’s for enable/disable
sequence of software data protection. If there are any questions , please contact with Renesas
Technology’s sales offices.
Rev.5.00, Nov. 17.2003, page 19 of 22