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.