HN58S65A Datasheet, PDF (15/18 Pages) Hitachi Semiconductor – 64 k EEPROM (8-kword x 8-bit) Ready/Busy function

HN58S65A Series
Data Protection
1. Data Protection against Noise on Control Pins (CE, OE, WE) during Operation
During readout or standby, noise on the control pins may act as a trigger and turn the EEPROM to
programming mode by mistake.
To prevent this phenomenon, this device has a noise cancellation function that cuts noise if its width is
15 ns or less.
Be careful not to allow noise of a width of more than 15 ns on the control pins.
WE
CE
V_IH
0V
V_IH
OE
0V
15 ns max
2. Data protection at V_CC on/off
When V_CC is turned on or off, noise on the control pins generated by external circuits (CPU, etc) may
act 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 should be kept in unprogrammable state during V_CC on/off by using CPU
RESET signal.
V_CC
CPU
RESET
* _{Unprogrammable}
* _{Unprogrammable}