S-24CS16A Datasheet, PDF (18/53 Pages) Seiko Instruments Inc – 2-WIRE CMOS SERIAL E2PROM

2-WIRE CMOS SERIAL E²PROM
S-24CS16A
Rev.4.3_00
7. 2 Random Read
Random read is used to read the data at an arbitrary memory address.
A dummy write is performed to load the memory address into the address counter.
When the E²PROM receives a 7-bit device address and a 1-bit read / write instruction code set to “0” following a
start condition, it responds with an acknowledge. The E²PROM then receives an 8-bit word address and responds
with an acknowledge. The memory address is loaded to the address counter in the E²PROM by these operations.
Reception of write data does not follow in a dummy write whereas reception of write data follows in a byte write and
in a page write.
Since the memory address is loaded into the memory address counter by dummy write, the master device can read
the data starting from the arbitrary memory address by transmitting a new start condition and performing the same
operation in the current address read.
That is, when the E²PROM receives a 7-bit device address and a 1-bit read / write instruction code set to “1”,
following a start condition signal, it responds with an acknowledge. Next, 8-bit data is transmitted from the
E²PROM in synchronous to the SCL clock. The master device outputs stop condition not an acknowledge, the
reading of E²PROM is ended.
S
W
T
R
A
I
S
T
A
R
E
NO ACK from
Master Device
S
T
R
DEVICE
T
R
DEVICE ^A
O
T ADDRESS ^E WORD ADDRESS (n) T
ADDRESS D
DATA
P
SDA
LINE
1 0 1 0 P2 P1 P0 0 _{W7 W6 W5 W4 W3 W2 W1 W0}
1 0 1 0 P2 P1 P0 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 19 Random Read
18
Seiko Instruments Inc.