HN58S65A Datasheet, PDF (16/18 Pages) Hitachi Semiconductor – 64 k EEPROM (8-kword x 8-bit) Ready/Busy function

HN58S65A Series
(1) Protection by CE, OE, WE
To realize the unprogrammable state, the input level of control pins must be held as shown in the table
below.
CE
V_CC
×
×
OE
×
V_SS
×
WE
×
×
V_CC
×: Don’t care.
V_CC: Pull-up to V_CC level.
V_SS: Pull-down to V_SS level.
3. Software data protection
To prevent unintentional programming caused by noise generated by external circuits, this device has
the software data protection function. In software data protection mode, 3 bytes of data must be input
before write data as follows. And these bytes can switch the non-protection mode to the protection
mode. SDP is enabled if onry the 3 byte code is input.
Address
Data
1555
AA
↓
↓
0AAA
55
↓
↓
1555
A0
↓
↓
Write address Write data } Normal data input
Software data protection mode can be canceled by inputting the following 6 bytes. After that, this
device turns to the non-protection mode and can write data normally. But when the data is input in the
canceling cycle, the data cannot be written.
Address
1555
↓
0AAA
↓
1555
↓
1555
↓
0AAA
↓
1555
Data
AA
↓
55
↓
80
↓
AA
↓
55
↓
20
The software data protection is not enabled at the shipment.
Note: There are some differences between Hitachi’s and other company’s for enable/disable sequence
of software data protection. If there are any questions , please contact with Hitachi sales
offices.