Техническая Спецификация для Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105
Модели
ATEVK1105
503
AT32UC3A
30.7
Functional Description
30.7.1
USB General Operation
30.7.1.1
Introduction
After a hardware reset, the USB controller is disabled. When enabled, the USB controller runs
either in device mode or in host mode according to the ID detection.
If the USB_ID pin is not connected to ground, the ID bit is set by hardware (the internal pull-up
If the USB_ID pin is not connected to ground, the ID bit is set by hardware (the internal pull-up
resistor of the USB_ID pin must be enabled by the GPIO controller) and device mode is
engaged.
The ID bit is cleared by hardware when a low level has been detected on the USB_ID pin. Host
The ID bit is cleared by hardware when a low level has been detected on the USB_ID pin. Host
mode is then engaged.
30.7.1.2
Power-On and Reset
describes the USB controller main states.
Figure 30-5.
General States
After a hardware reset, the USB controller is in the Reset state. In this state:
•the macro is disabled (USBE = 0);
•the macro clock is stopped in order to minimize power consumption (FRZCLK = 1);
•the pad is in suspend mode;
•the internal states and registers of the device and host modes are reset;
•the DPRAM is not cleared and is accessible;
•the ID and VBUS read-only bits reflect the states of the USB_ID and VBUS input pins;
•the OTGPADE, VBUSPO, FRZCLK, USBE, UIDE, UIMOD and LS bits can be written by
•the macro clock is stopped in order to minimize power consumption (FRZCLK = 1);
•the pad is in suspend mode;
•the internal states and registers of the device and host modes are reset;
•the DPRAM is not cleared and is accessible;
•the ID and VBUS read-only bits reflect the states of the USB_ID and VBUS input pins;
•the OTGPADE, VBUSPO, FRZCLK, USBE, UIDE, UIMOD and LS bits can be written by
software, so that the user can program pads and speed before enabling the macro, but their
value is only taken into account once the macro is enabled and unfrozen.
After setting USBE, the USB controller enters the Device or the Host mode (according to the ID
detection) in idle state.
The USB controller can be disabled at any time by clearing USBE. In fact, clearing USBE acts
The USB controller can be disabled at any time by clearing USBE. In fact, clearing USBE acts
as a hardware reset, except that the OTGPADE, VBUSPO, FRZCLK, UIDE, UIMOD and LS bits
are not reset.
Device
Reset
USBE = 0
<any
other
other
state>
USBE = 1
ID = 1
Macro off:
USBE = 0
Clock stopped:
FRZCLK = 1
USBE = 0
Host
USBE = 0
HW
RESET
USBE = 1
ID = 0
32058K
AVR32-01/12