USB 2.0 Hi-Speed 2-Port Hub Controller

 

 

 

Datasheet

 

Table 3.1 USB2512A Pin Descriptions (continued)

 

 

 

 

 

QFN-36

BUFFER

 

SYMBOL

EMB

TYPE

DESCRIPTION

 

 

 

 

XTAL2

32

OCLKx

Crystal Output

 

 

 

24MHz Crystal

 

 

 

This is the other terminal of the crystal, or a NO CONNECT

 

 

 

when an external clock source is used to drive XTAL1/CLKIN.

 

 

 

Note: This output must not be used to drive any external

 

 

 

circuitry other than the crystal circuit.

 

 

 

 

RESET_N

26

IS

RESET Input

 

 

 

The system can reset the chip by driving this input low. The

 

 

 

minimum active low pulse is 1 us.

 

 

 

When the RESET_N pin is pulled to VDD33, the internal POR

 

 

 

(Power on Reset) is enabled and no external reset circuitry is

 

 

 

required. The internal POR holds the internal logic in reset until

 

 

 

the power supplies are stable.

 

 

 

 

SUSP_IND/

28

I/O

Active/Suspend status LED or Local-Power & Non-removable

LOCAL_PWR/

 

 

Strap Option

NON_REM0

 

 

Suspend Indicator: Indicates USB state of the hub.

 

 

 

 

 

 

‘negated’ = Unconfigured, or configured and in USB Suspend

 

 

 

‘asserted’ = Hub is configured, and is active (i.e., not in

 

 

 

suspend)

 

 

 

 

 

 

 

Local Power: Detects availability of local self-power source.

 

 

 

Low = Self/local power source is NOT available (i.e., Hub gets

 

 

 

all power from Upstream USB VBus).

 

 

 

High = Self/local power source is available.

 

 

 

NON_REM0 Strap Option:

 

 

 

If this strap is enabled by package and configuration settings

 

 

 

(see Table 3.2), this pin will be sampled (in conjunction with

 

 

 

NON_REM1) at RESET_N negation to determine if ports [2:1]

 

 

 

contain permanently attached (non-removable) devices. Also,

 

 

 

the active state of the LED

 

 

 

will be determined as follows:

 

 

 

NON_REM[1:0] = ‘00’, All ports are removable, and the LED is

 

 

 

active high

 

 

 

NON_REM[1:0] = ‘01’, Port 1 is non-removable, and the LED

 

 

 

is active low

 

 

 

NON_REM[1:0] = ‘10’, Ports 1 & 2 are non-removable, and the

 

 

 

LED is active high

 

 

 

NON_REM[1:0] = ‘11’, Ports 1 & 2 are non-removable, and the

 

 

 

LED is active low

 

 

 

 

TEST

11

IPD

TEST pin

 

 

 

XNOR continuity tests all signal pins on the hub. Please contact

 

 

 

your SMSC representative for a detailed description of how this

 

 

 

test mode is enabled and utilized.

 

 

 

 

Revision 1.96 (07-11-08)

10

SMSC USB2512A

 

DATASHEET