3.3 TUSB2E11 Functional Modes
3.3.1 I2C Mode
When SDA and SCL are pulled high at reset, the TUSB2E11 is in I2C Mode, where the TUSB2E11 typically acts
as an eUSB2 to USB repeater. The repeater can be further configured using the 1.8 V I2C interface accessible
at J6. I2C configuration, however, is not required for the repeater to operate. Please note that GPIO0 must be
pulled high for normal I2C repeater mode operation.
3.3.2 GPIO Mode
The TUSB2E11 repeater can also be configured by strap settings instead of I2C. When SCL is low at reset,
the TUSB2E11 will use the strap settings on the GPIOs to determine the repeater configuration. Please see the
TUSB2E11 data sheet for more information.
3.3.3 UART Mode
In UART mode, the TUSB2E11 acts a UART to UART repeater to support in-system debug. UART mode can
be entered by pulling the GPIO0 low when the TUSB2E11 is in I2C mode or by setting SCL high and SDA low
at reset, and setting the GPIO0 low. If SCL is high and SDA is low at reset, and GPIO0 is pulled high, then the
TUSB2E11 will be in a non-functional state.
4 TUSB2E11EVM Internal Lab Use Only
There are several features of the TUSB2E11EVM that are reserved for internal lab use only.
1. Under normal use conditions, the resistor on R18 should not be installed. In addition, adding the resistors and
capacitor, R12, R14, and C3 is not recommended for end users.
2. 1.2 V IO operation is not enabled on the default TUSB2E11EVM.
3. The VBUS control functions implemented by U5 and U6 are not currently supported.
5 Layout Notes
The TUSB2E11EVM was laid out with the following considerations:
• USB signals impedance controlled 90 Ω differential ± 5%
• eUSB signals impedance controlled 45 Ω signal ended ± 5%
• USB 2.0 and eUSB signal pairs routed with matched trace lengths and minimal vias.
• All other signals to be impedance controlled 45 Ω ± 10% or 50 Ω ± 10%
General information about the PCB is provided below:
• Finished board thickness: .062 ± 10% – necessary for socket
• Copper weight: 1 oz start internal, 1/2 oz start external
• Laminate material: FR4 Polyclad 370 or equivalent
A four layer stack-up was used for the TUSB2E11EVM.
Drill notes on board stack up to account for the small BGA breakout:
1. L1 – L2 (laser drill) used for small pitch BGA break out
2. L2 – L3 (mechanical drill) completes the small pitch BGA breakout
3. L3 – L4 (laser drill) for VPP
EVM Configuration Using Jumpers
4
TUSB2E11 Evaluation Module User's Guide
SLLU229 – MAY 2022
Copyright © 2022 Texas Instruments Incorporated
