Universal Serial Bus (USB)
Am186™CC/CH/CU Microcontrollers User’s Manual
18-5
Figure 18-3
USB With External Transceiver
If necessary, to enable interface signals for an external transceiver, disable the integrated
USB transceiver by asserting the USBXCVR pinstrap at reset (power-on or assertion of
RES). Table 18-1 on page 18-3 lists all USB signals, plus information about multiplexed
functions.
Note: Before using either the internal USB transceiver or the external USB transceiver
interface, software must set the PUP_XCVER bit in the USB Device Miscellaneous
Functions (USBMFR) register to power up the USB transceiver and enable the transceiver
interface.
18.3.1.3
USB Clock Source
The USB peripheral controller hardware requires a 48-MHz clock input for proper operation.
The USB peripheral controller can be driven directly from the primary system clock if the
primary system clock is operating at 48 MHz. Otherwise, use a dedicated USB clock source
so that the primary microcontroller system clock and the USB clock are independent of
each other. When the dedicated USB clock source is used, the only requirement is that
the
PIO_USB_DETECT
PIO_USB_VCC
D
G
S
D
S
G
USB Type “B”
V
USB
USBD–
USBD+
GND
1
2
3
4
UTXDMNS[RSVRD_102]
UTXDPLS[RSVRD_101]
UXVOE[RSVRD_103]
UXVRCV[RSVRD_104]
UDMNS[USBD–]
UDPLS[USBD+]
1.5 K-
Ω
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 documentation for the external transceiver.
Am186CC/CU
Microcontroller
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...