2014 Microchip Technology Inc. DS20005265A-page 13
25LC512
2.6 Data Protection
The following protection has been implemented to
prevent inadvertent writes to the array:
The write enable latch is reset on power-up
A write enable instruction must be issued to set
the write enable latch
After a byte write, page write or STATUS register
write, the write enable latch is reset
•CS
must be set high after the proper number of
clock cycles to start an internal write cycle
Access to the array during an internal write cycle
is ignored and programming is continued
2.7 Power-On State
The 25LC512 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-level transition on CS
is required to
enter active state
TABLE 2-4: WRITE-PROTECT FUNCTIONALITY MATRIX
WEL
(SR bit 1)
WPEN
(SR bit 7)
WP
(pin 3)
Protected Blocks Unprotected Blocks STATUS Register
0xx
Protected Protected Protected
10x
Protected Writable Writable
110 (low)
Protected Writable Protected
111 (high)
Protected Writable Writable
x = don’t care
25LC512
DS20005265A-page 14 2014 Microchip Technology Inc.
2.8 PAGE ERASE
The PAGE ERASE instruction will erase all bits (FFh)
inside the given page. A Write Enable (WREN) instruc-
tion must be given prior to attempting a PAGE ERASE.
This is done by setting CS
low and then clocking out
the proper instruction into the 25LC512. After all eight
bits of the instruction are transmitted, the CS must be
brought high to set the write enable latch.
The PAGE ERASE instruction is entered by driving CS
low, followed by the instruction code (Figure 2-8) and
two address bytes. Any address inside the page to be
erased is a valid address.
CS
must then be driven high after the last bit of the
address or the PAGE ERASE will not execute. Once
the CS is driven high the self-timed PAGE ERASE
cycle is started. The WIP bit in the STATUS register
can be read to determine when the PAGE ERASE cycle
is complete.
If a PAGE ERASE instruction is given to an address
that has been protected by the Block Protect bits (BP0,
BP1) then the sequence will be aborted and no erase
will occur.
FIGURE 2-8: PAGE ERASE SEQUENCE
SO
SI
SCK
CS
0 234567891011 2122231
0000010115 14 13 12 210
Instruction 16-bit Address
High-Impedance
2014 Microchip Technology Inc. DS20005265A-page 15
25LC512
2.9 SECTOR ERASE
The SECTOR ERASE instruction will erase all bits
(FFh) inside the given sector. A Write Enable (WREN)
instruction must be given prior to attempting a SECTOR
ERASE. This is done by setting CS
low and then clock-
ing out the proper instruction into the 25LC512. After
all eight bits of the instruction are transmitted, the CS
must be brought high to set the write enable latch.
The SECTOR ERASE instruction is entered by driving
CS
low, followed by the instruction code (Figure 2-9)
and two address bytes. Any address inside the sector
to be erased is a valid address.
CS
must then be driven high after the last bit of the
address or the SECTOR ERASE will not execute. Once
the CS is driven high the self-timed SECTOR ERASE
cycle is started. The WIP bit in the STATUS register
can be read to determine when the SECTOR ERASE
cycle is complete.
If a SECTOR ERASE instruction is given to an address
that has been protected by the Block Protect bits (BP0,
BP1) then the sequence will be aborted and no erase
will occur.
See Table 2-3 for Sector Addressing.
FIGURE 2-9: SECTOR ERASE SEQUENCE
SO
SI
SCK
CS
0 234567891011 2122231
0011011015 14 13 12 210
Instruction 16-bit Address
High-Impedance

25LC512-M/SN

Mfr. #:
Manufacturer:
Microchip Technology
Description:
EEPROM Serial EEPROM 512K 64K X 8, 2.5V MIL T
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet