SMSC USB20H04 - Manual (Page 24)

4-Port USB 2.0 Hub Controller
Datasheet
Revision 1.63 (03-30-07) Page 24 SMSC USB20H04
DATASHEET
Table 8.6 - Default Configuration Values
REGISTER
ADDRESS
REGISTER NAME
SELF-POWERED
DEFAULT (HEX)
BUS-POWERED
DEFAULT (HEX)
01h VID MSB 04 04
02h VID LSB 24 24
03h PID MSB ** **
04h PID LSB 00 00
05h DID MSB 00 00
06h DID LSB 00 00
07h Config Data Byte 3 58 98
08h Config Data Byte 2 00 08
09h Config Data Byte 1 05 05
0Ah Max Power 00 64
0Bh Hub Controller Max Current 00 64
0Ch Power-on Time 80 80
** The default PID value is dependent on the silicon revision.
8.4 Reset
There are two different resets that the USB20H04 will experience. One is a hardware reset (via the
RESET_N pin) and the second a USB Reset.
8.4.1 External Hardware Reset
A valid hardware reset is initiated by the assertion of RESET_N for a minimum of 100ns after all power
supplies are within operating range.
Assertion of RESET_N (external pin) causes the following:
1. All downstream ports are disabled, and V
BUS
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, and no states are saved.
4. All internal registers return to the default state (in most cases, 00(h)).
5. LED indicators are disabled
After RESET_N is negated, the USB20H04 is ready to be configured as an SMBus slave (if SMB_SEL_N
= 0) or it reads OEM specific data from the external EEPROM (if SMB_SEL_N = 1). Default values for
configuration data are loaded if the SELF ONLY default strapping option is selected, or if an EEPROM is
not present. The timing associated with these options is shown in the tables below.