TUSB2036

2/3-PORT HUB FOR THE UNIVERSAL SERIAL BUS

WITH OPTIONAL SERIAL EEPROM INTERFACE

SLLS372 – MARCH 2000

5

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

VF

I/O

DESCRIPTION

BUSPWR

8

I

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 pin should be pulled

low, and for the self-powered mode, this pin should 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 three downstream USB ports.

DP0

1

I/O

Root port USB differential data plus. DP0 paired with DM0 constitutes the upstream USB port.

DP0PUR

27

O

Pull-up resistor connection. Whenever a system reset occurs (RESET being driven to low, but not USB reset)

or any logic level change on BUSPWR terminal, DP0PUR output goes to inactive Low until the internal counter

reaches a 3 ms time period. After the counter expires, DP0PUR is driven to the VCC (3.3 V) level thereafter

until the next system reset event or BUSPWR logic level change.

DP1 – DP3

12, 16,

20

I/O

USB differential data plus. DP1 – DP3 paired with DM1 – DM3 support up to three downstream USB ports.

EECLK

5

O

EEPROM serial clock. When EXTMEM is high, the EEPROM interface is disabled. The EECLK pin is disabled

and should 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.

EEDATA/

GANGED

6

I/O

EEPROM serial data/power management mode indicator. When EXTMEM is high, EEDATA/GANGED

selects between gang and per-port power overcurrent detection for the downstream ports. When EXTMEM

is low, 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.

EXTMEM

26

I

EEPROM read enable. When EXTMEM is high, the serial EEPROM interface of the device is disabled. When

EXTMEM is low, terminals 5 and 6 are configured as the clock and data pins of the serial EEPROM interface,

respectively.

GND

7, 28

Ground. GND terminals must be tied to ground for proper operation.

OCPROT/

PWRSW

21

I

Overcurrent Protection for bus-powered hub (active low). /Power Switching for self-powered hub (active low).

The pin has a different meaning for the bus or self-powered hub. If the pin is logic-high the internal pull-down

is disabled. (see Notes 1 and 2 ).

OVRCUR1 –

OVRCUR3

10, 14,

18

I

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 and all OVRCUR pins should be tied together. OVRCUR pins are active low inputs with noise filtering

logic. OVRCUR3 has an internal pull-up that can be enabled for the 2-port operation.

NOTES:

1. If the hub is implemented to be bus-powered (via BUSPWR tying to GND):

– TUSB2036 reports to the host that the hub end-product downstream ports are power-switched (this is required by the USB 1.1

Specification). Hub end product vendor has to ensure the actual end product implementation meets this specification requirement.

– Pin 21 acts as overcurrent protection (OCPROT) implementation indication pin for the bus-powered hub. The overcurrent

protection implementation is reported through the wHubCharacteristics. D4-bit in the hub descriptor.

– 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.

– 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 VCC),:

– TUSB2036 reports to the host that the hub end-product provides overcurrent protection to the downstream ports (this is required

by the USB 1.1 Specification). Hub end product vendor has to ensure the actual end-product implementation meets this

specification requirement.

– Pin 21 acts as power switching (PWRSW) implementation indication pin for the self-powered hub. The power switching

implementation is reported through the bPwrOn2PwrGood field in the hub descriptor.

– 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).

– 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).