Texas Instruments TUSB8020BPHP REVA User Manual page 6

1 Configuration Switches
The TI TUSB8020BEVM 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 TUSB8020B during power on reset, changing the switch settings while the EVM is powered on
has no effect. Refer to the EVM schematic in
The switch definitions are as follows, with the standard setting in parenthesis:
SW1_1 (on): FULLPWRMGMTZ_SMBA1_SS Switch. The TUSB8020B has an internal pull up on this
terminal, so the TUSB8020B 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
TUSB8020B reports that it supports downstream port power switching in the USB descriptors it sends to
the USB host. Since the TUSB8020B EVM does implement downstream port power switching, enable full
power management mode.
SW1_2 (off): PWRCTL_POL_SS_DN1 Switch. The TUSB8020B 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 TUSB8020B 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 TUSB8020B 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 TUSB8020B EVM does implement individual port
power controls, this terminal should be set high.
SW1_5 (off): SCL_SMBCLK Switch. The TUSB8020B 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 Switch. The TUSB8020B 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 TUSB8020B 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 TUSB8020B has an internal pull down on this terminal, so
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.
6
Hardware Set Up
Appendix B
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Hardware Set Up
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