SMSC USB2512Ai - Manual (Page 10)

Industrial Temperature Rated USB 2.0 Hi-Speed 2-Port Hub Controller
Datasheet
Revision 1.97 (08-11-08) 10 SMSC USB2512Ai
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.
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
μs.
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, "SMBus or EEPROM Interface Behavior" ), 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.
Table 3.1 USB2512Ai Pin Descriptions (continued)
SYMBOL
QFN-36
EMB
BUFFER
TYPE DESCRIPTION