U3280M_07 Datasheet, PDF (11/21 Pages) ATMEL Corporation – Transponder Interface for Microcontroller

U3280M
5.2.1.1
Write One Data Byte
5.2.1.2
START
Write Two Data Bytes
Control byte
A Data byte 1
A STOP
5.2.1.3
START Control byte A Data byte 1 A Data byte 2 A STOP
Write Control Byte Only
5.2.1.4
START Control byte
A →acknowledge
A STOP
Write Control 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)
5.2.2
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
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.
11
4688D–RFID–03/07