USB2412-DZK Standard Microsystems (SMSC), USB2412-DZK Datasheet - Page 14

• Manufacturer Part Number: USB2412-DZK
• Manufacturer: Standard Microsystems (SMSC)

Specifications of USB2412-DZK

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Chapter 4 Internal Default Configuration
Revision 1.0 (02-12-10)
4.1
4.1.1
4.2
4.2.1
SMSC’s USB 2.0 hub is fully specification compliant to the Universal Serial Bus specification, version
2.0, April 27, 2000 (12/7/2000 and 5/28/2002 Errata). Please reference Chapter 10 (Hub specification)
for general details regarding hub operation and functionality.
The hub provides 1 Transaction Translator (TT) that is shared by both downstream ports (defined as
Single-TT configuration). The TT contains 4 non-periodic buffers.
Hub Configuration
The USB2412 only supports internal defaults with the exception of the non-removable strap option
(NON_REM[1:0]). The hub internal default settings are as follows:
There are two different resets that the hub experiences. One is a hardware reset via the RESET_N
pin and the second is a USB Bus Reset.
External Hardware RESET_N
A valid hardware reset is defined as assertion of RESET_N for a minimum of 1 μs after all power
supplies are within operating range. While reset is asserted, the hub (and its associated external
circuitry) consumes less than 500 μA of current from the upstream USB power source.
Assertion of RESET_N (external pin) causes the following:
1. All downstream ports are disabled, and PRTPWR power to downstream devices is removed.
2. The PHYs are disabled, and the differential pairs will be in a high-impedance state.
3. All transactions immediately terminate; no states are saved.
4. All internal registers return to the default state (in most cases, 00(h)).
5. The external crystal oscillator is halted.
6. The PLL is halted.
7. The hub is “operational” 500 μs after RESET_N is negated.
Hub
Reset
Internal Default Configuration without any over-rides
Strap options enabled
Self-powered operation enabled
Individual power switching
Individual over-current sensing
DATASHEET
14
2-Port USB 2.0 Hi-Speed Hub Controller
SMSC USB2412
Datasheet