CMOS 2-WIRED SERIAL EEPROM
7.2 Random Read
Random read is a mode used when the data is read from arbitrary memory addresses.
To load a memory address into the address counter inside the EEPROM, first perform a dummy write
according to the following procedures:
When the EEPROM receives a 7-bit length device address and a 1-bit read/write instruction code "0,"
following the start condition signal, it outputs the acknowledgment signal.
Next, the EEPROM receives an 8-bit length word address and outputs the acknowledgment signal. Last,
the memory address is loaded into the address counter of the EEPROM.
the EEPROM receives the write data during byte or page writing. However, data reception is not
performed during dummy write.
The memory address is loaded into the memory address counter inside the EEPROM during dummy write.
After that, the master device can read the data starting from the arbitrary memory address by transmitting
a new start condition signal and performing the same operation as that in the "Current Read."
That is, when the EEPROM receives a 7-bit length device address and a 1-bit read/write instruction code
"1," following the start condition signal, it outputs the acknowledgment signal.
Next, 8-bit length data is output from the EEPROM, in synchronization with the SCL clock. The master
device does not output an acknowledgment signal and transmits the stop condition signal to finish reading.
E WORD ADDRESS (n)
NO ACK from
1 0 1 0 A2 A1 A0 0 W7W6W5W4W3W2W1W0
1 0 1 0 A2 A1 A0 1 D7 D6 D5 D4 D3 D2 D1 D0
M LR A
S S/ C
B BW K
W7 is optional in the S-24C01A.
A0 is P0 in the S-24C04A.
Figure 13 Random Read
12 Seiko Instruments Inc.