USB 2.0 HSIC Hi-Speed 4-Port Hub Controller
Datasheet
Table 3.1 Pin Descriptions (continued)
BUFFER
NUM PINS
NAME
SYMBOL
OCS1_N
OCS2_N
UART_RX
TYPE
DESCRIPTION
MISC.
Port 1 Over-
Current
Sense Input
IS
(PU)
This active-low signal is input from an external
current monitor to indicate an over-current
condition on USB Port 1.
1
1
Port 2 Over-
Current
Sense Input
IS
(PU)
This active-low signal is input from an external
current monitor to indicate an over-current
condition on USB Port 2.
UART
IS
Internal UART receive input
Receive Input
Note:
This is a 3.3V signal. For RS232
operation, an external 12V translator is
required.
1
Port 3 Over-
Current
Sense Input
OCS3_N
IS
(PU)
This active-low signal is input from an external
current monitor to indicate an over-current
condition on USB Port 3.
UART
Transmit
Output
UART_TX
O8
Internal UART transmit output
Note:
This is a 3.3V signal. For RS232
operation, an external 12V driver is
required.
1
Port 4 Over-
Current
Sense Input
OCS4_N
IS
(PU)
This active-low signal is input from an external
current monitor to indicate an over-current
condition on USB Port 4.
SystemReset
Input
RESET_N
I_RST
This active-low signal allows external hardware to
reset the device.
Note:
The active-low pulse must be at least
5us wide. Refer to Section 8.4.2,
"External Chip Reset (RESET_N)," on
page 56 for additional information.
1
1
Crystal Input
XTAL1
ICLK
ICLK
External 24 MHz crystal input
Reference
Clock Input
REFCLK
Reference clock input. The device may be
alternatively driven by a single-ended clock
oscillator. When this method is used, XTAL2
should be left unconnected.
Crystal
Output
XTAL2
RBIAS
OCLK
AI
External 24 MHz crystal output
1
1
External USB
Transceiver
Bias Resistor
A 12.0kΩ (+/- 1%) resistor is attached from
ground to this pin to set the transceiver’s internal
bias settings.
Revision 1.0 (06-17-13)
16
SMSC USB4604
DATASHEET
SMSC [ SMSC CORPORATION ]
