Product specifications

VT8237R Data Sheet
Revision 2.06 December 15, 2004 -94- Device 16 Function 5 USB Direct Device Communications Registers
Offset 15-14 – USB Device Interrupt Enable (0000h) ....RW
15-4 Reserved ........................................ always reads 0
3 Controller System Error Interrupt Enable
0 Disable ...................................................default
1 Enable (the controller will generate an
interrupt if a system error occurs)
2 Bus Activities Interrupt Enable
0 Disable ...................................................default
1 Enable (the controller will generate an
interrupt if any bus activity occurs - bus
activities include bus reset, bus suspend and
bus resume)
1 Reserved ........................................ always reads 0
0 Transaction Complete Interrupt Enable
0 Disable ...................................................default
1 Enable (the controller will generate an
interrupt on completion of a transaction)
Offset 17-16 – USB Device Port Control Status (1000h) WC
15-13 Reserved for Test (Do Not Program).... default = 0h
12 Device Port Power Control................................ RW
This bit enables power on the device port connector.
0 Disable Port Power
1 Enable Port Power ................................ default
11 Reserved ........................................always reads 0
10 USB Host Controller Is Using This Device PortRO
Indicates if UHCI or EHCI is using the device port.
9 USB Bus Line Status (D+) .................................. RO
8 USB Bus Line Status (D–)................................... RO
Bits 8-9 show the current state of the USB signals.
7 Pullup Resistor Status......................................... RO
Indicates whether the pullup resistor is connected. If
connected, the host is not USB 2.0 capable.
0 Not connected........................................ default
1 Connected
6 Termination Resistor Status............................... RO
Indicates whether the termination resistor is
connected. If connected, the host is USB 2.0 capable.
0 Not connected........................................ default
1 Connected
5 Reserved ........................................always reads 0
4 Port Owner ........................................................ RW
This bit selects the owner of the dedicated port. This
bit is set by the device controller in automatic mode.
0 Host owned............................................ default
1 Device owned
3 Pullup Resistor ................................................... RW
This bit enables the 1.5K ohm pullup resistor of the
D+ line. This bit is used only in manual mode.
0 Disable................................................... default
1 Enable
2 Termination Resistor ......................................... RW
This bit enables the 45 ohm termination resistor.
This bit is used only in manual mode.
0 Disable................................................... default
1 Enable
1 Connection Change ....................... Write 1 to Clear
0 No change.............................................. default
1 Status changed (set if the bit-0 state changes)
0 Remote Host Connected...................................... RO
0 Not connected........................................ default
1 Connected (set if the remote host is connected
to the device port)
Offset 18 – Device Mode Listen Timeout (10h).............. RW
7-0 Device Mode Listen Timeout Parameter... def=10h
Offset 19 – Host Mode Waiting Timeout (10h) .............. RW
7-0 Host Mode Waiting Timeout Parameter... def=10h