MB85RC04VPNF-G Datasheet, PDF (6/36 Pages) Fujitsu Component Limited. – 4 K (512 × 8) Bit I2C

MB85RC04V
■ DEVICE ADDRESS WORD
Following the start condition, the 8 bit device address word is input. Inputting the device address word decides
whether writing or reading operation. However, the clock is always driven by the master. The device address
word (8 bits) consists of a device Type code (4 bits), device address code (2 bits), memory upper address
code (1 bit), and a Read/Write code (1 bit).
• Device Type Code (4 bits)
The upper 4 bits of the device address word are a device type code that identifies the device type, and are
fixed at “1010” for the MB85RC04V.
• Device Address Code (2 bits): A1, A2
Following the device type code, the 2 bits of the device address code are input in order of A2 and A1.
The device address code identifies one device from up to 4 devices connected to the bus.
Each MB85RC04V is given a unique 2 bits code on the device address pin (external hardware pin A2 and
A1). The slave only responds if the received device address code is equal to this unique 2 bits code.
• Memory Upper Address Code (1 bit): A8
Following the device address code, the 1-bit memory upper address code are input.
This bit is not the setting bit for the slave address, but the upper 1-bit setting bit for the memory address.
• Read/Write Code (1 bit)
The 8th bit of the device address word is the R/W (Read/Write) code. When the R/W code is “0” input, a
write operation is enabled, and the R/W code is “1” input, a read operation is enabled for the MB85RC04V.
If the device type code is not “1010” or the device address code is not equal to the setting of the external
device address pins, the Read/Write operation is not performed and the standby state is chosen.
• Device Address Word
Start 1 2 3 4 5 6 7 8 9 1 2
SCL
..
SDA
ACK
S ^{1 0 1 0} A2 A1 A8 R/W A
..
Device Type Code
Read/Write Code
Device Address Code Memory Upper Address Code
Access from master
Access from slave
S Start Condition
A ^{ACK (SDA is the "L" level)}
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DS501-00016-2v0-E