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Hardware Set Up

3

Hardware Set Up

3.1

Configuration Switch

The TI TUSB4020BEVM has a set of switches to facilitate configuration changes. Changing these switch

settings without a complete understanding of the result is not recommended. Configuration inputs are only

read by the TUSB4020B during power on reset, changing the switch settings while the EVM is powered on

will have no effect. Please refer to the EVM schematic in Appendix B for additional information.

The switch definitions are as follows, with the standard setting in parenthesis:

SW1_1 (on):

FULLPWRMGMTZ_SMBA1_SS Switch. The TUSB4020B has an internal pull up on

this terminal, so the TUSB4020B defaults to a non full power management mode. If the

switch is set to the ON position, the terminal is pulled low and full power management

mode is enabled. This means that the TUSB4020B reports that it supports downstream

port power switching in the USB descriptors it sends to the USB host. Since the

TUSB4020B EVM does implement downstream port power switching, full power

management mode should be enabled.

SW1_2 (off):

PWRCTL_POL_SS_DN1 Switch. The TUSB4020B has an internal pull down on this

terminal, so port power control polarity defaults to active high. If the switch is set to the

ON position, the terminal is pulled high and the port power control polarity changes to

active low.

SW1_3 (off):

SMBUSz_SS_DN2 Switch. The TUSB4020B has an internal pull up on this terminal,

so I2C interface mode is enabled by default. If the switch is set to the ON position, the

terminal is pulled low and SMBUS mode is enabled.

SW1_4 (on):

GANGED_SMBA2_HS Switch. The TUSB4020B has an internal pull up on this

terminal, so ganged mode is enabled by default. If the switch is set to the ON position,

the terminal is pulled low and individual port power control mode is enabled. Since the

TUSB4020B EVM does implement individual port power controls, this terminal should

be set high.

SW1_5 (off):

SCL_SMBCLK_SSCDIS Switch. The TUSB4020B has an internal pull down on this

terminal, so the serial EEPROM/SMBUS interface is disabled. If the switch is set to the

ON position, a pull-up resistor is connected to the serial clock terminal to indicate that

an I2C EEPROM may be attached (along with a pull-up resistor on SDA).

SW1_6 (off):

SDA_SMBDAT_U1U2DIS Switch. The TUSB4020B has an internal pull down on this

terminal, so the serial EEPROM/SMBUS interface is disabled. If the switch is set to the

ON position, a pull-up resistor is connected to the serial clock terminal to indicate that

an I2C EEPROM may be attached (along with a pull-up resistor on SCL).

SW1_7 (off):

PWRCTL1_BATEN1 Switch. The TUSB4020B has an internal pull down on this

terminal, so USB Battery Charging mode on Port 1 is disabled by default. If the switch

is set to the ON position, the terminal is pulled high and battery charging is enabled on

downstream port 1.

SW1_8(off):

PWRCTL2_BATEN2 Switch. The TUSB4020B has an internal pull down on this

terminal, so the USB Battery Charging mode on Port 2 is disabled by default. If the

switch is set to the ON position, the terminal is pulled high and battery charging is

enabled on downstream port 2.

5

SLLU219 – June 2015

TUSB4020BPHP Evaluation Module

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