BU99901GUZ-W Datasheet, PDF (9/12 Pages) Rohm – Silicon Monolithic Integrated Circuit

9/11
○ACKNOWLEDGE
・Acknowledge is a software convention used to indicate successful data transfers.
The transmitter device will release the bus after transmitting eight bits.
(When inputting the slave address in the write or read operation, transmitter is μ-COM.
When outputting the data in the read operation, it is this device.)
・During the ninth clock cycle, the receiver will pull the SDA line LOW to acknowledge
that the eight bits of data has been received.
(When inputting the slave address in the write or read operation, receiver is this
device. When outputting the data in the read operation, it is μ-COM.)
・The device will respond with an Acknowledge after recognition of a START condition
and its slave address (8bit).
・In the WRITE mode, the device will respond with an Acknowledge, after the receipt of
each subsequent 8-bit word (word address and write data).
・In the READ mode, the device will transmit eight bit of data, release the SDA line,
and monitor the line for an Acknowledge.
・If an Acknowledge is detected, and no STOP condition is generated by the master,
the device will continue to transmit the data.
If an Acknowledge is not detected, the device will terminate further data transmissions
and await a STOP condition before returning to the standby mode.
(See Fig.-7 ACKNOWLEDGE RESPONSE FROM RECEIVER)
START CONDITION
(START BIT)
SCL
（Fromμ-COM）
1
8
9
SDA
（μ-COM
OUTPUT DATA)
SDA
（IC OUTPUT DATA）
Acknowledge Signal
Fig.-7 ACKNOWLEDGE RESPONSE FROM RECEIVER ^{(ACK Signal)}
◇BYTE WRITE
SDA
LINE
S
W
T
R
A
R
T
SLAVE
ADDRESS
I
T
E
1st WORD
ADDRESS
10100 00
WA
* * * * ₁₁
2nd WORD
ADDRESS
DATA
WA
0 ^D7
RA
A
A
/C
C
C
WK
K
K
WP
S
T
O
P
D0
A
C
K
Fig.-8 BYTE WRITE CYCLE TIMING
* : Don’t care
○By using this command, the data is programed into the indicated word address.
○When the master generates a STOP condition, the device begins the internal
write cycle to the nonvolatile memory array.
REV. A