Rainbow Electronics BR24L08FVM-W - Manual (Page 8)

BR24L08-W / BR24L08F-W / BR24L08FJ-W
Memory ICs BR24L08FV-W / BR24L08FVM-W
8/25
zDevice operation
1) Start condition (Recognition of start bit)
• All commands are proceeded by the start condition, which is a HIGH to LOW transition of SDA when SCL is HIGH.
• The device continuously monitors the SDA and SCL lines for the start condition and will not respond to any command
until this condition has been met. (See Fig.4 SYNCHRONOUS DATA TIMING)
2) Stop condition (Recognition of stop bit)
• All communications must be terminated by a stop condition, which is a LOW to HIGH transition of SDA when SCL is
HIGH. (See Fig.4 SYNCHRONOUS DATA TIMING)
3) Notice about write command
• In the case that stop condition is not executed in WRITE mode, transferred data will not be written in a memory.
4) Device addressing
• Following a START condition, the master output the slave address to be accessed.
• The most significant four bits of the slave address are the “device type identifier”, for this device it is fixed as “1010”.
• The next bit (device address) identify the specified device on the bus.
The device address is defined by the state of A2 input pin. This IC works only when the device address
inputted from SDA pin correspond to the state of A2 input pin. Using this address scheme, up to two devices may be
connected to the bus.
• The next two bits (P1, P0) are used by the master to select t four 256 word page of memory.
P1, P0 set to “0” “0” - - - - - - 1page (000 to 0FF)
P1, P0 set to “0” “1” - - - - - - 2page (100 to 1FF)
P1, P0 set to “1” “0” - - - - - - 3page (200 to 2FF)
P1, P0 set to “1” “1” - - - - - - 4page (300 to 3FF)
• The last bit of the stream (R/W - - - READ / WRITE) determines the operation to be performed. When set to “1”, a read
operation is selected ; when set to “0”, a write operation is selected.
R / W set to “0” - - - - - - WRITE (including word address input of Random Read)
R / W set to “1” - - - - - - READ
A2 P1 P0 1010 R / W
5) Write protect (WP)
When WP pin set to V
CC (H level), write protect is set for 1024 words (all address).
When WP pin set to GND (L level), enable to write 1024 words (all address).
Either control this pin or connect to GND (or V
CC ). It is inhibited from being left unconnected.