BR24L02-W Rohm Semiconductor, BR24L02-W Datasheet - Page 11

• Manufacturer Part Number: BR24L02-W
• Description: IC EEPROM 2KBIT 400KHZ 8DIP
• Manufacturer: Rohm Semiconductor

Specifications of BR24L02-W

• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Memory Size: 2K (256 x 8)
• Speed: 400kHz
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 1.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

●Software reset
●Acknowledge polling
Software reset is executed when to avoid malfunction after power on, and to reset during command input. Software reset has
several kinds, and 3 kinds of them are shown in the figure below. (Refer to Fig.48(a), Fig.48(b), and Fig.48(c).) In dummy
clock input area, release the SDA bus ('H' by pull up). In dummy clock area, ACK output and read data '0' (both 'L' level) may
be output from EEPROM, therefore, if 'H' is input forcibly, output may conflict and over current may flow, leading to
instantaneous power failure of system power source or influence upon devices.
During internal write execution, all input commands are ignored, therefore ACK is not sent back. During internal automatic
write execution after write cycle input, next command (slave address) is sent, and if the first ACK signal sends back 'L', then it
means end of write action, while if it sends back 'H', it means now in writing. By use of acknowledge polling, next command
can be executed without waiting for tWR = 5ms.
When to write continuously, R/W = 0, when to carry out current read cycle after write, slave address R/W = 1 is sent, and if
ACK signal sends back 'L', then execute word address input and data output and so forth.
SCL
SDA
SCL
SDA
SCL
SDA
…
Fig.49 Case to continuously write by acknowledge polling
S
T
A
R
T
First write command
Fig.48-(b) The case of START +9 dummy clocks +START+ command input
Fig.48-(a) The case of dummy clock +START+START+ command input
S
T
A
R
T
Write command
Fig.48-(c) START×9+ command input
Slave
address
t
WR
Start
1
1
A
C
K
H
Dummy clock×14
2
1
S
T
O
P
2
Dummy clock×9
S
T
A
R
T
2
3
Slave
address
S
T
A
R
T
Start×9
Slave
address
13
11/32
Second write command
A
C
K
L
14
8
7
After completion of internal write,
ACK=LOW is sent back, so input next
word address and data in succession.
A
C
K
H
Word
address
t
WR
9
Start×2
8
During internal write,
ACK = HIGH is sent back.
S
T
A
R
T
Start
※
Slave
address
A
C
K
L
9
Start command from START input.
Data
A
C
K
H
A
C
K
L
S
T
O
P
Normal command
Normal command
Normal command
Normal command
Normal command
Normal command