Datasheet

 2017 Microchip Technology Inc. DS60001516A-page 671

SAM9G20

36.5.3.8 Sending a Device Remote Wakeup

In Suspend state it is possible to wake up the host sending an external resume.

• The device must wait at least 5 ms after being entered in suspend before sending an external resume.

• The device has 10 ms from the moment it starts to drain current and it forces a K state to resume the host.

• The device must force a K state from 1 to 15 ms to resume the host

To force a K state to the bus (DM at 3.3V and DP tied to GND), it is possible to use a transistor to connect a pullup on DM. The K state is

obtained by disabling the pullup on DP and enabling the pullup on DM. This should be under the control of the application.

Figure 36-15: Board Schematic to Drive a K State

3V3

PIO

1.5 K

0: Force Wake UP (K State)

1: Normal Mode