LM3S5652 Luminary Micro, Inc, LM3S5652 Datasheet - Page 616

• Manufacturer Part Number: LM3S5652
• Description: Lm3s5652 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

Univeral Serial Bus (USB) Controller
616
Bit/Field
1:0
2
EPENDE
Name
EPEN
Type
R/W
R/W
Reset
0x00
0
Preliminary
Description
EPEN Drive Enable
Specifies whether the USB0EPEN signal is driven or undriven (tristate).
When driven, the signal value is specified by the EPEN bit. When not
driven, the EPEN bit is ignored and the USB0EPEN signal is placed in a
high-impedance state.
The USB0EPEN is undriven at reset since the sense of the external power
supply enable is unknown. By adding high-impedance state, system
designers may bias the power supply enable to the disabled state using
a large resistor (100 kΩ) and later configure and drive the output signal
to enable the power supply.
External Power Supply Enable Configuration
Specifies and controls the logical value driven on the USB0EPEN signal.
Value
0
1
Value
0x0
0x1
0x2
0x3
Description
Not Driven
The USB0EPEN signal is high impedance.
Driven
The USB0EPEN signal is driven to the logical value specified by
the EPEN bit value.
Description
Power Enable Active Low
The USB0EPEN signal is driven Low if EPENDE is 1.
Power Enable Active High
The USB0EPEN signal is driven High if EPENDE is 1.
Power Enable High if VBUS Low
The USB0EPEN signal is driven High when the A device is not
recognized.
Power Enable High if VBUS High
The USB0EPEN signal is driven High when the A device is
recognized.
June 02, 2008