AT24C01D and AT24C02D [DATASHEET]

Atmel-8871B-SEEPROM-AT24C01D-02D-Datasheet_032014

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5.4

Write Cycle Timing

the internal Write operation, to the Start condition of the first Device Address byte sent to the AT24C01D/02D

which it subsequently responds to with an ACK. Figure 5-4 has been included to show this measurement. During

the internally self-timed write cycle, any attempts to read or write to the memory array will not be processed.

Figure 5-4.

Write Cycle Timing

5.5

Write Protection

The AT24C01D/02D utilizes a hardware data protection scheme that allows the user to write protect the entire

or left floating.

Table 5-1.

AT24C01D/02D Write Protect Behavior

The status of the WP pin is sampled at the Stop condition for every Byte Write or Page Write command prior to the

start of an internally self-timed Write operation. Changing the WP pin state after the Stop condition has been sent

will not alter or interrupt the execution of the write cycle. The WP pin state must be valid with respect to the

time that the WP state must be stable before the Stop condition is issued. The WP hold time is the amount of time

after the Stop condition that the WP state must remain stable.

If an attempt is made to write to the device while the WP pin has been asserted, the device will acknowledge the

Device Address, Word address, and Data bytes but no write cycle will occur when the Stop condition is issued, and

the device will immediately be ready to accept a new Read or Write command.

Figure 5-5.

Write Protect Setup and Hold Timing

t

WR

Stop

Condition

Start

Condition

Data Word n

ACK

D0

SDA

Stop

Condition

SCL

89

ACK

First Acknowledge from the device

to a valid device address sequence after

write cycle is initiated. The minumum t

WR

can only be determined through

the use of an ACK Polling routine.

9

WP Pin Voltage

Part of the Array Protected

Full Array

GND

None — Write Protection Not Enabled

SCL

SDA IN

1

2

7

8

9

D7

D6

D1

D0

WP

Stop

by

Master

Data Word Input Sequence Page/Byte Write Operation

ACK by Slave