Datasheet

39.5.3 USB Host Operation
39.5.3.1 Description of Pipes
For the USBHS in Host mode, the term “pipe” is used instead of “endpoint” (used in Device mode). A host pipe
corresponds to a device endpoint, as described in Figure 39-16 (from the USB Specification).
Figure 39-16. USB Communication Flow
In Host mode, the USBHS associates a pipe to a device endpoint, considering the device configuration descriptors.
39.5.3.2 Power-On and Reset
The following figure describes the USBHS Host mode main states.
Figure 39-17. Host Mode Main States
Ready
Idle
Device
Disconnection
<any
other
state>
Device
Connection
Macro off
Clock stopped
Device
Disconnection
Suspend
SOFE = 1
SOFE = 0
After a hardware reset, the USBHS Host mode is in the Reset state.
When the USBHS is enabled (USBHS_CTRL.USBE = 1) in Host mode (USBHS_CTRL.UIMOD = 0), it goes to the
Idle state. In this state, the controller waits for a device connection with a minimal power consumption. The USB pad
should be in the Idle state. Once a device is connected, the USBHS enters the Ready state, which does not require
the USB clock to be activated.
The controller enters the Suspend state when the USB bus is in a “Suspend” state, i.e., when the Host mode does
not generate the “Start of Frame (SOF)”. In this state, the USB consumption is minimal. The Host mode exits the
Suspend state when starting to generate the SOF over the USB line.
39.5.3.3 Device Detection
A device is detected by the USBHS Host mode when D+ or D- is no longer tied low, i.e., when the device D+ or D-
pull-up resistor is connected. The bit USBHS_SFR.VBUSRQS must be set to ‘1’ to enable this detection.
Note: The VBUS supply is not managed by the USBHS interface. It must be generated on-board.
The device disconnection is detected by the host controller when both D+ and D- are pulled down.
SAM E70/S70/V70/V71 Family
USB High-Speed Interface (USBHS)
© 2019 Microchip T
echnology Inc.
Datasheet
DS60001527D-page 767