R1EX24512BSAS0A Datasheet, PDF (9/19 Pages) Renesas Technology Corp – Two-wire serial interface 512k EEPROM (64-kword × 8-bit)

R1EX24512BSAS0A/R1EX24512BTAS0A
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 code 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 A2-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 A2.
Device Address Word
Device address word (8-bit)
Device code (fixed)
Device address code
512k
1
0
1
0
A2
A1
A0
Notes: 1. R/W=“1” is read and R/W = “0” is write.
R/W code*¹
R/W
R10DS0025EJ0001 Rev.0.01
Sep, 01, 2010
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