AT30TSE004_14 Datasheet, PDF (39/47 Pages) ATMEL Corporation – Integrated Temperature Sensor with Serial EEPROM

8.4.2
Random Read
A Random Read operation allows the Master to access any memory location in a random manner and requires a dummy
write sequence to preload the starting data word address. To perform a Random Read, the device address byte and the
word address byte are transmitted to the AT30TSE004 as part of the dummy write sequence (see Figure 8-10). Once the
device address byte and data word address are clocked in and acknowledged by the AT30TSE004, the Master must
generate another Start condition. The Master initiates a Current Address Read by sending another device address byte
with the R/W select bit to a Logic 1. The AT30TSE004 acknowledges the device address byte, increments its internal
address counter and serially clocks out the first data word. The device will continue to transmit sequential data words as
long as the Master continues to ACK each data word. To end the sequence, the Master responds with a NACK and a
Stop condition.
Figure 8-10. Random Read from Serial EEPROM
SCL
SDA
Start
by
Master
12 3 4 567 89 12 345 67 89
Device Address Byte
Word Address Byte
1 0 1 0 A2 A1 A0 0 0 A7 A6 A5 A4 A3 A2 A1 A0 0
MSB
MSB
ACK
from
Slave
Dummy Write
ACK
from
Slave
12 3 4 567 89 12 345 67 89
Device Address Byte
Data Word (n)
Start
by
Master
1 0 1 0 A2 A1 A0 1 0 D7 D6 D5 D4 D3 D2 D1 D0 1
MSB
MSB
ACK
from
Slave
NACK
from
Master
Stop
by
Master
Atmel AT30TSE004 [PRELIMINARY DATASHEET] 39
8816B–DTS–12/2012