Operation
2014 Microchip Technology Inc.
DS50002252A-page 19
trol
array location. Set the RESET_N pin low to reset the part and place it into the low-
est power state. If the CONNECT pin is low when the RESET pin transitions from low
to high, the USB3503 will remain in a state that allows the serial interface registers to
be manipulated. To enumerate the hub, either write 00h to register E7h, or drive the
CONNECT pin high by pressing the
CONNECT
button in the
Digital Control
. Once the
USB3503 has enumerated, the serial interface registers should not be modified.
3.3.2
I
2
C
Communication
The application also contains a general I
2
C register read/write section. The
Bit
and
Description
display the serial interface register descriptions found in the USB3503
data sheet. The
Register
display can be used to select the proper serial interface reg-
ister to manipulate. Click on the
Value
or
Bit
box above to change the value of the reg-
ister. Once the desired value and register are selected, press the
Write
button to
change the value on the part. Click on the
Read
button and the
Value
and
Bit
boxes
will update the current value on the part. Refer to the USB3503 data sheet for a detailed
description of each register and operation of the device.
3.3.3
Quick Configuration and Customization
The USB3503 Evaluation program also contains some quick configuration and custom-
ization options that automatically update the registers to match the desired configura-
tion. The USB3503 can enumerate as a Self Powered or Bus Powered Hub with 1, 2
or 3 downstream ports. The VID, PID, DID and enumeration strings can also be cus-
tomized to allow the USB3503 to enumerate with whatever identification is desired.
Note:
To prevent the Aardvark from driving against another voltage, the Aardvark
is running in an Open/Drain mode. Therefore it is important that all switches
on the board pull the pins up to the VCC value.
FIGURE 3-3:
DIGITAL CONTROL (GREEN) AND REGISTERS (YELLOW)
