Datasheet

TUSB2036
SLLS372F –MARCH 2000–REVISED SEPTEMBER 2013 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 low, and
BUSPWR 8 I
for the self-powered mode, this terminal must be pulled to 3.3 V. Input must not change dynamically during
operation.
DM0 2 I/O Root port USB differential data minus. DM0 paired with DP0 constitutes the upstream USB port.
DM1–DM3 11, 15, 19 I/O USB differential data minus. DM1–DM3 paired with DP1–DP3 support up to four downstream USB ports.
DP0 1 I/O Root port USB differential data plus. DP0 paired with DM0 constitutes the upstream USB port.
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 reaches a
DP0PUR 27 O
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.
DP1–DP3 12, 16, 20 I/O USB differential data plus. DP1–DP3 paired with DM1–DM3 support up to four downstream USB ports.
EEPROM serial clock. When EXTMEM is high, the EEPROM interface is disabled. The EECLK terminal is
EECLK 5 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,
6 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 5
EXTMEM 26 I
and 6 are configured as the clock and data terminals of the serial EEPROM interface, respectively.
GND 7, 28 GND terminals must be tied to ground for proper operation.
Overcurrent Protection for bus-powered hub (active low). /Power Switching for self-powered hub (active low). The
OCPROT/
21 I terminal has a different meaning for the bus or self-powered hub. If the terminal is logic high the internal pulldown
PWRSW
is disabled.
(1) (2)
Overcurrent input. OVRCUR1 − OVRCUR3 are active low. For per-port overcurrent detection, one overcurrent
input is available for each of the three downstream ports. In the ganged mode, any OVRCUR input may be used
OVRCUR1 −
10, 14, 18 O and all OVRCUR terminals must be tied together. OVRCUR terminals are active low inputs with noise filtering
OVRCUR3
logic. Each OVRCURn input is sampled every 2 ms and any input which is valid for two consecutive samples will
be passed to the internal logic. OVRCUR3 has an internal pull-up that can be enabled for the 2-port operation.
Power-on/-off control signals. PWRON1–PWRON3 are active low, push-pull outputs that enables the external
PWRON1 – power switch device. Push-pull outputs eliminate the pullup resistors which open-drain outputs require. However,
9, 13, 17 O
PWRON3 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 4 I all logic is initialized. Generally, a reset with a pulse width between 100 μs and 1 ms is recommended after 3.3-V
V
CC
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 32 O
suspend mode, SUSPND is high. SUSPND is low for normal operation.
Mode select. When MODE is low, the APLL output clock is selected as the clock source to drive the internal core
MODE 31 of the device and 6-MHz crystal or oscillator can be used. When MODE is high, the clock on XTAL1/CLK48 is
selected as the clock source and 48-MHz oscillator or other on-board clock source can be used.
Number of ports is 3. Active low input. A logic 0 configures the system to use 3 ports. A logic 1 configures the
NP3 24
system to use 2 ports.
NPINT1−0 22, 23 Number of ports internal to hub system, which are permanently attached (see Table 1).
(1) If the hub is implemented to be bus-powered (via BUSPWR tying to GND):
(a) TUSB2036 reports to the host that the hub end-product downstream ports are power-switched (this is required by the USB 2.0
specification). Hub end-product vendor has to ensure the actual end-product implementation meets this specification requirement.
(b) Terminal 21 acts as overcurrent protection (OCPROT) implementation indication terminal for the bus-powered hub. The overcurrent
protection implementation is reported through the wHubCharacteristics. D4 bit in the hub descriptor.
(c) When OCPROT is low, the TUSB2036 reports to the host that the hub end-product provides overcurrent protection and the
wHubCharacteristics. D4 bit is set to 0.
(d) When OCPROT is high, the TUSB2036 reports to the host that the hub end-product does not provide overcurrent protection and the
wHubCharacteristics. D4 bit is set to 1.
(2) If the hub is implemented to be self-powered (via BUSPWR tying to 3.3-V V
CC
):
(a) TUSB2036 reports to the host that the hub end-product provides overcurrent protection to the downstream ports (this is required by
the USB 2.0 specification). Hub end-product vendor has to ensure the actual end-product implementation meets this specification
requirement.
(b) Terminal 21 acts as power switching (PWRSW) implementation indication terminal for the self-powered hub. The power-switching
implementation is reported through the bPwrOn2PwrGood field in the hub descriptor.
(c) When PWRSW is low, the TUSB2036 reports to the host that the hub end-product has port power switching at the downstream ports
and the bPwrOn2PwrGood is set to 50 units (100 ms).
(d) When PWRSW is high, the TUSB2036 reports to the host that the hub end-product does not have port power switching at the
downstream ports and the bPwrOn2PwrGood is set to 0 units (0 ms).
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