10

Atmel U3280M [DATASHEET]

4688E–RFID–05/13

5.2.1.4 Write Control Bytes

5.2.2

Read Operations

The EEPROM allows byte-, word- and current address read operations. The read operations are initiated in the same way as

write operations. Each read access is initiated by sending the START condition followed by the control byte which contains the

address and the read mode. When the device has received a read command, it returns an acknowledge, loads the addressed

word into the read/write buffer and sends the selected data byte to the master. The master has to acknowledge the received

byte to proceed with the read operation. If two bytes are read out from the buffer, the device automatically increments or

decrements the word address and loads the buffer with the next word. The read mode bit determines if the low or high byte is

read first from the buffer and if the word address is incremented or decremented for the next read access. When the memory

address limit has been reached, the data word address will “roll over” and the sequential read will continue. The master can

terminate the read operation after every byte by not responding with an acknowledge (N) and by issuing a STOP condition.

5.2.2.1 Read One Data Byte

5.2.2.2 Read Two Data Bytes

5.2.2.3 Read n Data Bytes

Write Low Byte First

MSB

LSB

A4

A3

A2

A1

A0

C1

C0

R/NW

Row address

0

1

0

Byte Order

LB(R)

HB(R)

Write High Byte First

MSB

LSB

A4

A3

A2

A1

A0

C1

C0

R/NW

Row address

1

0

0

Byte Order

HB(R)

LB(R)

HB: high byte; LB: low byte; R: row address

START

Control byte

A Data byte 1

N STOP

START

Control byte

A Data byte 1

A Data byte 2

N STOP

START Control byte

A Data byte 1 A Data byte 2 A - - - - - - Data byte n N STOP

A

→acknowledge, N →no acknowledge