u3280m ATMEL Corporation, u3280m Datasheet - Page 11

• Manufacturer Part Number: u3280m
• Description: Transponder Interface For Microcontroller U3280m
• Manufacturer: ATMEL Corporation

5.2.1.1
5.2.1.2
5.2.1.3
5.2.1.4
5.2.2
4688D–RFID–03/07
Read Operations
Write One Data Byte
Write Two Data Bytes
Write Control Byte Only
Write Control Bytes
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.
START
START
START
A
Write Low Byte First
Byte Order
Write High Byte First
Byte Order
HB: high byte; LB: low byte; R: row address
MSB
MSB
A4
A4
acknowledge
HB(R)
LB(R)
Control byte
Control byte
Control byte
A3
A3
Row address
Row address
A2
A2
A STOP
A
A Data byte 1
HB(R)
LB(R)
Data byte 1
A1
A1
A Data byte 2
A STOP
A0
A0
C1
C1
0
1
A STOP
C0
C0
1
0
R/NW
R/NW
LSB
LSB
U3280M
0
0
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