
XRA1203
5
REV. 1.0.0
16-BIT I2C/SMBUS GPIO EXPANDER WITH RESET
1.1.1
I2C-bus Addressing
There could be many devices on the I2C-bus. To distinguish itself from the other devices on the I2C-bus, the
XRA1203 has up to 16 I2C slave addresses using the A1-A0 address lines. Table 1 below shows the different addresses that can be selected.
TABLE 1: I C ADDRESS MAP
C ADDRESS
SCL
GND
0x20 (0010 000X)
SCL
VCC
0x22 (0010 001X)
SDA
GND
0x24 (0010 010X)
SDA
VCC
0x26 (0010 011X)
SCL
0x30 (0011 000X)
SCL
SDA
0x32 (0011 001X)
SDA
SCL
0x34 (0011 010X)
SDA
0x36 (0011 011X)
GND
0x40 (0100 000X)
GND
VCC
0x42 (0100 001X)
VCC
GND
0x44 (0100 010X)
VCC
0x46 (0100 011X)
GND
SCL
0x50 (0101 000X)
GND
SDA
0x52 (0101 001X)
VCC
SCL
0x54 (0101 010X)
VCC
SDA
0x56 (0101 011X)
1.1.2
I2C Read and Write
A read or write transaction is determined by bit-0 of the slave address. If bit-0 is ’0’, then it is a write
transaction. If bit-0 is ’1’, then it is a read transaction.
2
A1
A0
I2