SMSC USB2512i - Manual (Page 10)

Industrial Temperature Rated USB 2.0 High-Speed 2-Port Hub Controller
Datasheet
Revision 1.92 (11-28-07) 10 SMSC USB2512i
DATASHEET
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.
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/
LOCAL_PWR/
NON_REM0
28 I/O Active/Suspend status LED or Local-Power & Non Removable
Strap Option
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 nonremovable, 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
Used for testing the chip. User must treat as a no-connect or
connect to ground.
Table 3.2 SMBus or EEPROM Interface Behavior
CFG_SEL1 CFG_SEL0 SMBUS OR EEPROM INTERFACE BEHAVIOR
0 0 Internal Default Configuration
„
Strap Options Enabled
Table 3.1 USB2512i Pin Descriptions (continued)
SYMBOL
QFN-36
EMB
BUFFER
TYPE DESCRIPTION