AT34C02C View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
AT34C02C
Atmel Corporation
'AT34C02C' PDF : 18 Pages View PDF
PERMANENT SOFTWARE WRITE PROTECTION: The software write protection is enabled by
sending a command, similar to a normal write command, to the device which programs the per-
manent write protect register. This must be done with the WP pin low. The write protect register
is programmed by sending a write command with the device address of 0110 instead of 1010
with the address and data bit being don’t cares (see Figure 7 on page 8). Once the software
write protection has been enabled, the device will no longer acknowledge the 0110 control byte.
The software write protection cannot be reversed even if the device is powered down. The write
cycle time must be observed.
REVERSIBLE SOFTWARE WRITE PROTECTION: The reversible software write protection is
enabled by sending a command, similar to a normal write command, to the device which pro-
grams the reversible write protect register. This must be done with the WP pin low. The write
protect register is programmed by sending a write command 01100010 with pins A2 and A1 tied
to ground or don't connect and pin A0 connected to VHV (see Figure 8). The reversible write
protection can be reversed by sending a command 01100110 with pin A2 tied to ground or no
connect, pin A1 tied to VCC and pin A0 tied to VHV (see Figure 9).
HARDWARE WRITE PROTECTION: The WP pin can be connected to VCC, GND, or left float-
ing. Connecting the WP pin to VCC will write protect the entire array, regardless of whether or not
the software write protection has been enabled. The software write protection register cannot be
programmed when the WP pin is connected to VCC. If the WP pin is connected to GND or left
floating, the write protection mode is determined by the status of the software write protect
register.
Figure 7. Setting Permanent Write Protect Register (PSWP)
S
T
CONTROL
A
BYTE
R
T
WORD
ADDRESS
S
DATA
T
O
P
SDA LINE
0 1 1 0 A2 A1 A0 0
A
A
A
C
C
C
K
K
K
= Don't Care
Figure 8. Setting Reversible Write Protect Register (RSWP)
SDA LINE
S
T
CONTROL
A
BYTE
R
T
WORD
ADDRESS
S
DATA
T
O
P
01100 010
A
A
A
C
C
C
K
K
K
= Don't Care
Figure 9. Clearing Reversible Write Protect Register (RSWP)
SDA LINE
S
T
CONTROL
A
R
BYTE
T
WORD
ADDRESS
S
DATA
T
O
P
01100 110
A
A
A
C
C
C
K
K
K
= Don't Care
8 AT34C02C
5242B–SEEPR–01/09
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