25AA640 MICROCHIP [Microchip Technology], 25AA640 Datasheet - Page 10

• Manufacturer Part Number: 25AA640
• Description: 64K SPI Bus Serial EEPROM
• Manufacturer: MICROCHIP [Microchip Technology]

25AA640/25LC640/25C640
3.7
The following protection has been implemented to pre-
vent inadvertent writes to the array:
• The write enable latch is reset on power-up.
• A write enable instruction must be issued to set
• After a byte write, page write, or status register
• CS must be set high after the proper number of
• Access to the array during an internal write cycle
TABLE 3-3:
DS21223A-page 10
the write enable latch.
write, the write enable latch is reset.
clock cycles to start an internal write cycle.
is ignored and programming is continued.
WPEN
X
X
0
1
Data Protection
High
Low
WP
WRITE PROTECT FUNCTIONALITY MATRIX
X
X
WEL
0
1
1
1
Protected Blocks
Protected
Protected
Protected
Protected
Preliminary
3.8
The 25xx640 powers on in the following state:
• The device is in low power standby mode (CS = 1).
• The write enable latch is reset.
• SO is in high impedance state.
• A high to low transition on CS is required to enter
.
the active state.
Unprotected Blocks
Power On State
Protected
Writable
Writable
Writable
1997 Microchip Technology Inc.
Status Register
Protected
Protected
Writable
Writable