HN58X24512I Datasheet, PDF (11/20 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
11