chipKIT Uno32 I²C to Serial Shield
Here are come notes about the Breakout Board for SC16IS750 I2C/SPI-to-UART IC implementation:
When using the chipKIT card, 10 kΩ pull-up resistors (R1 and R2) are required between SCL and +5V, also between SDA and +5V.
The Arduino board doesn't need them because there already built in.
The height Inputs / Ouputs can also be used.
I2C address is set according to a0/a1 pins:
_address=0x48; // a0/a1=+/+
if (n==1) _address=0x49; // a0/a1=-/+
else if (n==2) _address=0x4c; // a0/a1=+/-
else if (n==12) _address=0x4d; // a0/a1=-/-