
TUSB2077A
SLLS414D –MARCH 2000–REVISED AUGUST 2011
www.ti.com
TERMINAL FUNCTIONS
TERMINAL I/O DESCRIPTION
NAME NO.
Power source indicator. BUSPWR is an active-low input that indicates whether the downstream ports source
their power from the USB cable or a local power supply. For the bus-power mode, this terminal must be pulled
BUSPWR 10 I low, and for the self-powered mode, this terminal must be pulled to 3.3 V. Input must not change dynamically
during operation.
DM0 4 I/O Root port USB differential data minus. DM0 paired with DP0 constitutes the upstream USB port.
13, 17, 21, 26,
DM1–DM7 I/O USB differential data minus. DM1–DM7 paired with DP1–DP7 support up to four downstream USB ports.
30, 34, 38
DP0 3 I/O Root port USB differential data plus. DP0 paired with DM0 constitutes the upstream USB port.
14, 18, 22, 27,
DP1–DP7 I/O USB differential data plus. DP1–DP7 paired with DM1–DM7 support up to four downstream USB ports.
31, 35, 39
Pullup resistor connection. When a system reset happens (RESET being driven to low, but not USB reset) or
any logic level change on BUSPWR terminal, DP0PUR output is inactive (floating) until the internal counter
DP0PUR 2 O reaches a 15-ms time period. After the counter expires, DP0PUR is driven to the VCC (3.3 V) level thereafter
until the next system reset event occurs or there is a BUSPWR logic level change.
EEPROM serial clock. When EXTMEM is high, the EEPROM interface is disabled. The EECLK terminal is
EECLK 7 O disabled and must be left floating (unconnected). When EXTMEM is low, EECLK acts as a 3-state serial clock
output to the EEPROM with a 100-μA internal pulldown.
EEPROM serial data/power-management mode indicator. When EXTMEM is high, EEDATA/GANGED selects
EEDATA/ between ganged or per-port power overcurrent detection for the downstream ports. When EXTMEM is low,
8 I/O
GANGED EEDATA/GANGED acts as a serial data I/O for the EEPROM and is internally pulled down with a 100-μA
pulldown. This standard TTL input must not change dynamically during operation.
When EXTMEM is high, the serial EEPROM interface of the device is disabled. When EXTMEM is low, terminals
EXTMEM 47 I 7 and 8 are configured as the clock and data terminals of the serial EEPROM interface, respectively.
GND 5, 24, 43 GND terminals must be tied to ground for proper operation.
Hub configured. Used to control LED indicator. When the hub is configured, HUBCFG is high, which can be used
HUBCFG(1) 40 O to turn on a green LED. When the hub is not configured, HUBCFG is low, which can be used to turn on a red
LED.
Mode select. When MODE is low, the APLL output clock is selected as the clock source to drive the internal core
MODE 48 I of the chip and 6-MHz crystal or oscillator can used. When MODE is high, the clock on XTAL1/CLK48 is
selected as the clock source and 48-MHz oscillator or other onboard clock source can be used.
Overcurrent input. OVRCUR1–OVRCUR7 are active low. For per-port overcurrent detection, one overcurrent
OVRCUR1 –12, 16, 20, 25, input is available for each of the seven downstream ports. In the ganged mode, any OVRCUR input may be
I
OVRCUR7 29, 33, 37 used and all OVRCUR terminals must be tied together. OVRCUR terminals are active low inputs with noise
filtering logic.
Any port powered. Used to control LED indicator. When any port is powered on, PORTPWR is high, which can
PORTPWR(1) 41 O be used to turn on a green LED. When all ports are off, PORTPWR is low, which can be used to turn on a red
LED.
No ports disabled. PORTDIS is used for LED indicator control. When no port is disabled, PORTDIS is high,
PORTDIS(1) 42 O which can be used to turn on a green LED. When any port is disabled, PORTDIS is low, which can be used to
turn on a red LED.
Power-on/-off control signals. PWRON1–PWRON7 are active low, push-pull outputs that enables the external
PWRON1 –11, 15, 19, 23, power switch device. Push-pull outputs eliminate the pullup resistors which open-drain outputs require. However,
O
PWRON7 28, 32, 36 the external power switches that connect to these terminals must be able to operate with 3.3-V inputs because
these outputs cannot drive 5-V signals.
RESET is an active low TTL input with hysteresis and must be asserted at power up. When RESET is asserted,
RESET 6 I all logic is initialized. Generally, a reset with a pulse width between 100 μs and 1 ms is recommended after 3.3-V
VCC reaches its 90%. Clock signal has to be active during the last 60 μs of the reset window.
Suspend status. SUSPND is an active high output available for external logic power-down operations. During the
SUSPND 1 O suspend mode, SUSPND is high. SUSPND is low for normal operation.
VCC 9, 46 3.3-V supply voltage
Crystal 1/48-MHz clock input. When MODE is low, XTAL1/CLK48 is a 6-MHz crystal input with 50% duty cycle.
XTAL1/CLK48 45 I An internal APLL generates the 48-MHz and 12-MHz clocks used internally by the ASIC logic. When MODE is
high, XTAL1/CLK48 acts as the input of the 48-MHz clock and the internal APLL logic is bypassed.
XTAL2 44 O Crystal 2. XTAL2 is a 6-MHz crystal output. This terminal must be left open when using an oscillator.
(1) All LED controls are 3-stated during low-power suspend.
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