R1EX24512ASAS0A Datasheet, PDF (11/23 Pages) Renesas Technology Corp – Two-wire serial interface 512k EEPROM (64-kword × 8-bit)

R1EX24512ASAS0A
Device Addressing
The EEPROM device requires an 8-bit device address word following a start condition to enable the chip
for a read or a write operation. The device address word consists of 4-bit device code, 3-bit device
address code and 1-bit read/write(R/W) code. The most significant 4-bit of the device address word are
used to distinguish device type and this EEPROM uses “1010” fixed code. The device address word is
followed by the 3-bit device address code. The device address code selects one device out of all devices
which are connected to the bus. This means that the device is selected if the inputted 3-bit device address
code is equal to the corresponding hard-wired A1-A0 pin status. The eighth bit of the device address
word is the read/write(R/W) bit. A write operation is initiated if this bit is low and a read operation is
initiated if this bit is high. Upon a compare of the device address word, the EEPROM enters the read or
write operation after outputting the zero as an acknowledge. The EEPROM turns to a stand-by state if the
device code is not “1010” or device address code doesn’t coincide with status of the correspond hard-wired
device address pins A0 to A1.
Device Address Word
Device address word (8-bit)
Device code (fixed)
512k
1
0
1
0
Notes: 1. R/W=“1” is read and R/W = “0” is write.
2. Don’t care bit
Device address code
0*²
A1
A0
R/W code*¹
R/W
REJ03C0325-0100 Rev.1.00 May. 16, 2008
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