HN58X24512I Datasheet, PDF (11/19 Pages) Hitachi Semiconductor – Two-wire serial interface 512k EEPROM (64-kword ´ 8-bit)

HN58X24512I
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 upper bit of device address can be set any data. 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
to 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)
128k, 256k 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
Rev.2.00, Dec.13.2004, page 11 of 17