Universal Serial Bus (USB)
18-4
Am186™CC/CH/CU Microcontrollers User’s Manual
1.5 K-
Ω
pull up on USBD+ when V
USB
is removed. The following system design issues
should be resolved to provide a robust self-powered USB device application:
On Connect:
■
Monitor V
USB
to identify a powered USB host/hub.
■
Enable the 1.5 K-
Ω
pullup on USBD+ to signal a connect condition to the host/hub.
On Disconnect:
■
Monitor V
USB
to identify power being removed from the USB host/hub.
■
Three-state USBD+/USBD– outputs.
■
Remove power from 1.5 K-
Ω
pull up.
On both Connect and Disconnect:
■
Isolate V
USB
from the USB device when the device is unpowered.
Figure 18-2 illustrates a circuit diagram of an example application using the internal
transceiver. Figure 18-3 illustrates a circuit diagram of an example application using the
external transceiver.
Figure 18-2
USB With Internal Transceiver
Am186CC/CU
Microcontroller
D
G
S
D
S
G
1.5 K-
Ω
PIO_USB_DETECT
PIO_USB_VCC
USBD– [UDMNS]
USBD+ [UDPLS]
V
USB
USBD–
USBD+
GND
1
2
3
4
USB Type “B”
R1
R2
Note: The USB specification requires a driver impedance between 29
Ω
and 44
Ω
on the
USBD+ and USBD– signals. For information about driver characteristics and selecting a
series resistor value, see the data sheets for the Am186CC and Am186CU microcontrollers.
Содержание Am186 CC
Страница 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Страница 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Страница 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Страница 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Страница 39: ...Architectural Overview Am186 CC CH CU Microcontrollers User s Manual 1 15 Figure 1 6 32 Channel Linecard CH CC...
Страница 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Страница 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Страница 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Страница 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Страница 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...