AT28C64B-25 Просмотр технического описания (PDF) - Atmel Corporation
Номер в каталоге
Компоненты Описание
производитель
AT28C64B-25 Datasheet PDF : 20 Pages
| |||
tection Algorithms” on page 9.). After writing the 3-byte command sequence and waiting
tWC, the entire AT28C64B will be protected against inadvertent writes. It should be noted
that even after SDP is enabled, the user may still perform a byte or page write to the
AT28C64B by preceding the data to be written by the same 3-byte command sequence
used to enable SDP.
Once set, SDP remains active unless the disable command sequence is issued. Power
transitions do not disable SDP, and SDP protects the AT28C64B during power-up and
power-down conditions. All command sequences must conform to the page write timing
specifications. The data in the enable and disable command sequences is not actually
written into the device; their addresses may still be written with user data in either a byte
or page write operation.
After setting SDP, any attempt to write to the device without the 3-byte command
sequence will start the internal write timers. No data will be written to the device. How-
ever, for the duration of tWC, read operations will effectively be polling operations.
DEVICE IDENTIFICATION: An extra 64 bytes of EEPROM memory are available to the
user for device identification. By raising A9 to 12 V ±0.5 V and using address locations
1FC0H to 1FFFH, the additional bytes may be written to or read from in the same man-
ner as the regular memory array.
DC and AC Operating Range
AT28C64B-15
Operating
Temperature (Case)
VCC Power Supply
Com.
Ind.
0°C - 70°C
-40°C - 85°C
5 V ±10%
AT28C64B-20
0°C - 70°C
-40°C - 85°C
5 V ±10%
AT28C64B-25
0°C - 70°C
-40°C - 85°C
5 V ±10%
Operating Modes
Mode
CE
Read
VIL
Write(2)
VIL
Standby/Write Inhibit
VIH
Write Inhibit
X
Write Inhibit
X
Output Disable
X
Chip Erase
VIL
Notes: 1. X can be VIL or VIH.
2. See “AC Write Waveforms” on page 7.
3. VH = 12.0 V ±0.5 V.
OE
VIL
VIH
X(1)
X
VIL
VIH
VH(3)
WE
I/O
VIH
DOUT
VIL
DIN
X
High Z
VIH
X
X
High Z
VIL
High Z
4 AT28C64B
0270I–PEEPR–08/03
Share Link: 