BU9890GUL-W ROHM Co. Ltd., BU9890GUL-W Datasheet - Page 9

• Manufacturer Part Number: BU9890GUL-W
• Description: 4k?8 Bit Electrically Erasable Prom
• Manufacturer: ROHM Co. Ltd.

◇DEVICE OPERATION
○START CONDITION (RECOGNITION OF START BIT)
○STOP CONDITION (RECOGNITION OF STOP BIT)
○NOTICE ABOUT WRITE COMMAND
○DEVICE ADDRESSING
・The most significant four bits of the slave address are the “device type indentifier,”
・ The last bit of the stream (R/W … READ/WRITE) determines the operation to be
・All commands are proceeded by the start condition, which is a HIGH to LOW transition
・The device continuously monitors the SDA and SCL lines for the start condition and
・All commands must be terminated by a stop condition, which is a LOW to HIGH
・In the case that stop condition is not excuted in WRITE mode, transfered data will not
・Following a START condition, the master output the slave address to be accessed.
○WRITE PROTECT (WP)
（See Fig.-4 SYNCHRONOUS DATA TIMING）
（See Fig.-4 SYNCHRONOUS DATA TIMING）
performed. When set to “1”, a read operation is selected ; when set to “0”, a write
operation is selected.
of SDA when SCL is HIGH.
will not respond to any command until this condition has been met.
transition of SDA when SCL is HIGH.
be written in a memory.
for this device it is fixed as “1010” and next three bit set to “000”.
When WP pin set to V
When WP pin set to GND(L level), it is enable to write 4,096 words (all address).
Either control this pin or connect to GND ( or Vcc). It is inhibited from being left
unconnected.
R/W set to “0” ･ ･ ･ ･ ･ ･ ･ ･ WRITE (including word address input of Random Read)
R/W set to “1” ･ ･ ･ ･ ･ ･ ･ ･ READ
１ ０ １ ０
CC
０
(H level), write protect is set for 4,096 words (all address).
REV. A
０
０
Ｒ／Ｗ
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