MB85RC64
■ COMMAND
• Byte Write
If the 8th bit of the device address word (R/W = 0) is sent following the start condition, the slave responds
with an ACK. After this ACK, write addresses and data are sent in the same way, and the write ends by
master, generating a stop condition at the end.
Address
High 8bits
Address
Low 8bits
Write
Data 8bits
1
0 1 0 A2 A1 A0 0 A
A
A
A P
S
0 0 0 X X X X X
X X X X X X X X
Access from master
Access from slave
MSB
LSB
S
P
Start Condition
Stop Condition
A ACK
Note : In the MB85RC64, input “000” as the upper 3 bits of the MSB.
• Page Write
If additional 8bits are sent after the same command as Byte Write, a page write is performed. If more bytes
are sent than will fit up to the end of the address, the address rolls over to 0000H. Therefore, if more than
8KBytes are sent, the data is overwritten in order starting from the start of the FRAM memory address that
was written first. Because FRAM performs write operations at bus speed, the data will be written to FRAM
after the ACK response finishes immediately.
Address
High 8bits
Address
Low 8bits
Write
Data 8bits
Write
Data
...
1
0 1 0 A2 A1 A0 0 A
A
A
A
A
P
S
Access from master
Access from slave
S
P
Start Condition
Stop Condition
A ACK
Note : It is not necessary to take a period for internal write operation cycles from the buffer to the memory after
the stop condition is generated.
8
DS05–13109–3E
FUJITSU [ FUJITSU ]
