8
Typical hardware connection between USB-to-I2C and User Hardware
(Internal pull-up resistors jumpers at RPU)
USING USB-TO-I2C HARDWARE TO POWER USER’S SYSTEM
When connecting the USB-to-I2C Hardware to the user’s hardware, the target system can
be self-powered or it may be powered from the VCC, 3.3V or 5V connectors on the USB-to-
I2C hardware.
The 3.3V and 5V power outputs can be turned on and off using the USB-to-I2C software or
DLL. To turn on the power, select the appropriate item under the Options menu. A check
mark will be shown in the menu beside an enabled power output. The status bar at the
bottom of the USB-to-I2C software will also indicate if a power output is enabled. Note that
the 3.3V and 5V power outputs are disabled upon hardware reset.
To use the USB-to-I2C hardware in a 3.3V environment, you will need to connect the SCL,
SDA, GND and 3.3V (or the VCC pin) to your target system. The pull-up resistors may be left
in the circuit or they may be removed by removing the jumpers at RPU. If using the on-
board pull-up resistors, you should connect an appropriate voltage to VP.
USB-to-I2C Hardware used to power a user application
Important note: the total current consumed by the USB-to-I2C hardware and the target system must be
limited to 100mA by the user when using the power outputs. The USB-to-I2C hardware uses about
60mA so the target system can consume a maximum of 40mA.
