SMSC USB2524 - Manual (Page 15)

USB MultiSwitch TM Hub
Datasheet
SMSC USB2524 15 Revision 1.91 (08-22-07)
DATASHEET
1 0 0 Internal Default Configuration
„ PRT_ASSIGN[3:0] = Peripheral Mode (Edge Triggered)
„ LED Mode = Host Ownership Mode
„ Strap
„ options on pins LED_A[4:1]_N are enabled.
„ Supports unassigned Ports
1 0 1 Internal Default Configuration
„ PRT_ASSIGN[3:0] = Peripheral Mode (Edge Triggered)
„ LED Mode = Host Ownership & Port Speed Mode
„ Strap options on pins LED_A[4:1]_N are disabled
„ Supports unassigned Ports.
1 1 0 Reserved
1 1 1 Reserved
Table 4.3 Miscellaneous Pins
NAME SYMBOL TYPE FUNCTION
Crystal
Input/External
Clock Input
XTAL1/
CLKIN
ICLKx 24MHz crystal or external clock input.
This pin connects to either one terminal of the crystal or
to an external 24MHz clock when a crystal is not used.
Note: See Table 11.1 for the required logic voltage
levels of this pad if it will be driven by an
external clock source.
Crystal Output XTAL2 OCLKx 24MHz Crystal
This is the other terminal of the crystal, or left
unconnected when an external clock source is used to
drive XTAL1/CLKIN. It must not be used to drive any
external circuitry other than the crystal circuit.
RESET Input RESET_N IS This active low signal is used by the system to reset the
chip. The minimum active low pulse is 1us.
Self-Power /
Bus-Power
Detect
SELF_PWR I 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.
TEST Pin TEST IPD Used for testing the chip. User must treat as a no-
connect or connect to ground.
Table 4.4 Power, Ground, and No Connect
NAME SYMBOL TYPE FUNCTION
VDD Core VDDCR18 +1.8V core power.
Pins 16 and 50 must have a 4.7
μ
F (or greater) ±20%
(ESR <0.1
Ω)
capacitor to VSS
VDDIO 3.3V VDD33 +3.3V Power Supply for the Digital I/O.
Table 4.2 SMBus or EEPROM Interface Behavior (continued)
NAME NAME NAME FUNCTION