20H04 Datasheet, PDF (27/38 Pages) SMSC Corporation – 4-PORT USB2.0 HUB CONTROLLER

4-Port USB2.0 Controller
Datasheet
Table 8.6 - Default Configuration Values
REGISTER
ADDRESS
REGISTER NAME
01h
VID MSB
02h
VID LSB
03h
PID MSB
04h
PID LSB
05h
DID MSB
06h
DID LSB
07h
Config Data Byte 3
08h
Config Data Byte 2
09h
Config Data Byte 1
0Ah
Max Power
0Bh
Hub Controller Max Current
0Ch
Power-on Time
** The default PID value is dependent on the silicon revision.
SELF-POWERED
DEFAULT (HEX)
04
24
**
00
00
00
58
00
05
00
00
80
BUS-POWERED
DEFAULT (HEX)
04
24
**
00
00
00
98
08
05
64
64
80
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.
SMSC USB20H04
Page 27
DATASHEET
Revision 1.63 (10-14-04)