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4-Port USB 2.0 Controller
Datasheet
SMSC USB20H04 Page 23 Revision 1.63 (03-30-07)
DATASHEET
BIT FIELD NAME DESCRIPTION
3:0 Port Non-Active Selects which ports are active. A one indicates that the port is
non-active:
Bit 3: Port 4 is non-active.
Bit 2: Port 3 is non-active.
Bit 1: Port 2 is non-active.
Bit 0: Port 1 is non-active.
All zeroes sets all ports active.
Note: Active ports must be contiguous, and must start with port
number 1.
Table 8.4 - Address 8; Config_Byte_1
BIT FIELD NAME DESCRIPTION
7 Dynamic Power Selects the ability to transition to bus-powered operation if the local
power source is removed:
0: No dynamic auto-switching.
1: Dynamic auto-switching ability enabled.
6 On-The-Go Selects the ability to support an OTG host:
0: No OTG support.
1: OTG support enabled.
5:4 Reserved Set to zero.
3:0 Over-Current Timer Selects the over-current timer delay in 2 ms increments for the
active ports.
0101: delay is 2ms
1010: delay is 4ms
1111: delay is 6ms
Note: All other values are reserved
Table 8.5 - Addresses 9 - 11
BIT FIELD NAME DESCRIPTION
7:0 Max Power Current in 2mA increments that the 4-port hub consumes from an
upstream port in this configuration.
A value of 50, or 32(h), indicates 100 mA.
7:0 HubContrCurrent Absolute maximum current requirement in 2mA increments of the
hub controller electronics.
A value of 50, or 32(h), indicates 100 mA.
7:0 PwrOn2PwrGood Time in 2ms intervals from the time the power on sequence begins
on a port until power is good on that port.
A value of 50, or 32(h), indicates 100 ms.
8.3 Default Configuration Values
Default values for configuration data are loaded as described in section 8.1.2 and 8.1.3 above. The values
programmed are summarized in Table 8.6 - Default Configuration Values.