S-24C02BPPHL Datasheet, PDF (16/39 Pages) Seiko Instruments Inc – 2-WIRE CMOS SERIAL E2PROM

2-WIRE CMOS SERIAL E²PROM
S-24C02BPPHL
Rev.2.2_00
7.2 Random read
Random read is a mode used when data is read from arbitrary memory addresses.
To load a memory address into the address counter inside the E²PROM, first perform a dummy write
following the procedure below.
When the E²PROM receives a 7-bit device address and the 1-bit read/write instruction code “0” following the
start condition signal, it outputs the acknowledge signal.
Next, the E²PROM receives an 8-bit word address and outputs the acknowledge signal. The memory
address has now been loaded into the address counter of the E²PROM.
Following this, the E²PROM 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 E²PROM 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 Address Read”.
That is, when the E²PROM receives a 7-bit device address and the 1-bit read/write instruction code “1”
following the start condition signal, it outputs the acknowledge signal.
Next, 8-bit data is output from the E²PROM in synchronization with the SCL clock. The master device does
not output an acknowledge signal and transmits the stop condition signal instead. Reading is then complete.
S
W
S
T
R
T
R
A
I
A
E
R
DEVICE
T
R
DEVICE
A
T
ADDRESS
E
WORD ADDRESS (n)
T
ADDRESS
D
NO ACK from
master device
S
T
O
DATA
P
SDA
line
1 0 1 0 X XX 0
W7 W6 W5 W4 W3 W2 W1 W0
1 0 1 0 X X X 1 D7 D6 D5 D4 D3 D2 D1 D0
M
LR A
S
S/ C
B
BW K
AM
CS
KB
LR A
S/ C
BW K
ADR INC
DUMMY WRITE
Figure 14 Random Read
16
Seiko Instruments Inc.