10

Atmel AT30TSE002B [Preliminary]

8711D

−SEEPR−8/10

5.

Device Addressing

Atmel

to access either the Temperature Sensor or EEPROM functions (See Table 5-1).

Table 5-1.

Control/Device Address Word

Device

Control / Device Address Word

Device ID

Device Address Bits

R/W

B7

B6

B5

B4

A2

A1

A0

B0

EEPROM

1

0

1

0

X

X

X

X

Temperature Sensor

0

0

1

1

EEPROM Write Protection

0

1

1

0

Note:

X = User Selectable

The EEPROM device address word consists of a mandatory one-zero sequence for the first four most significant

bits (‘1010’) for normal read and write operations, a ‘0110’ for writing to the EEPROM write protect register and

‘0011’ for Temperature Sensor operations. The next three bits are the A2, A1 and A0 device address bits for the

AT30TSE002B device. These three bits must match their corresponding hard-wired input pins. The eighth bit of

the device address is the read/write operation select bit. A read operation is initiated if this bit is high and an

EEPROM write operation is selected if this bit is low. Upon a compare of the device address, the device will

output a zero, called an Acknowledge (ACK). If a compare is not made, the chip will not ACK and will return to a

standby state. The EEPROM will not ACK if the write protect register has been programmed and the control code

is ‘0110’.

6.

EEPROM Write Operations

BYTE WRITE: A write operation requires an 8-bit data word address following the device address word and ACK.

Upon receipt of this address, the EEPROM will again respond with an ACK and then clock in the first 8-bit data

word. Following receipt of the 8-bit data word, the EEPROM will output an ACK and the addressing device, such

as a microcontroller, must terminate the write sequence with a stop condition. At this time the EEPROM enters an

internally timed write cycle, t

EEPROM will not respond until the write is complete (see Figure 11-2 and Figure 11-3).

The device will acknowledge a write command, but not write the data, if the software write protection has been

enabled. The write cycle time must be observed even when the write protection is enabled.

PAGE WRITE: The 2K EEPROM device is capable of 16-byte page write. A page write is initiated the same as a

byte write, but the microcontroller does not send a stop condition after the first data word is clocked in. Instead,

after the EEPROM acknowledges receipt of the first data word, the microcontroller can transmit up to fifteen more

data words. The EEPROM will respond with a zero after each data word received. The microcontroller must

terminate the page write sequence with a stop condition (see Figure 11-3). The data word address lower four bits

are internally incremented following the receipt of each data word. The higher data word address bits are not

incremented, retaining the memory page row location. When the word address, internally generated, reaches the

page boundary, the following byte is placed at the beginning of the same page. If more than sixteen data words

are transmitted to the EEPROM, the data word address will “roll over” and previous data will be overwritten. The

address “roll over” during write is from the last byte of the current page to the first byte of the same page. The

device will acknowledge a write command, but not write the data, if the software write protection has been

enabled. The write cycle time must be observed even when the write protection is enabled.