HN58S256AT-20 HITACHI [Hitachi Semiconductor], HN58S256AT-20 Datasheet - Page 14

• Manufacturer Part Number: HN58S256AT-20
• Description: 256 k EEPROM (32-kword x 8-bit)
• Manufacturer: HITACHI [Hitachi Semiconductor]

HN58S256A Series
2. Data Protection at V
When V
as a trigger and turn the EEPROM to program mode by mistake. To prevent this unintentional
programming, the EEPROM must be kept in an unprogrammable state while the CPU is in an unstable
state.
Note: The EEPROM shoud be kept in unprogrammable state during V
To realize the unprogrammable state, the input level of control pins must be held as shown in the table
below.
CE
OE
WE
V
V
: Don’t care.
CC
SS
: Pull-up to V
: Pull-down to V
(1) Protection by CE, OE, WE
signal.
CC
is turned on or off, noise on the control pins generated by external circuits (CPU, etc) may act
CC
level.
SS
CPU
level.
RESET
V
CC
CC
On/Off
V
*
CC
Unprogrammable
V
SS
*
Unprogrammable
CC
on/off by using CPU RESET
V
CC