Register Map
13-27
USB Function Module
13.2.9.2
USB Reset Signaling (USB_Reset)
This bit returns 1 when the USB host is resetting the USB bus.
A valid USB reset resets all the endpoint FIFOS, all other control register bits
except Cfg_Lock, all associated configuration registers (0x20 to 0x3F), and
bits DS_Chg_IE and DS_Chg. This register (DEVSTAT) forces the device to
the default state. This bit is cleared at the end of reset.
This bit is double buffered just as the other DEVSTAT bits are. If there is a
pending interrupt that is not handle when a USB reset occurs, and if that inter-
rupt is handled only when USB reset is finished, the local host does not see
the USB_Reset bit going high and then low.
0: Device not being reset by USB host
1: Device is being reset by USB host
Value after local host reset is low and during USB reset is high (low after USB
reset).
13.2.9.3
Suspended State (SUS)
Device is, at minimum, attached to the USB and is powered, has been reset
by the USB host, and has not seen bus activity for 5 ms. It may also have a
unique address and be configured for use. However, because the device is
suspended, the host can not use the device function. This bit returns 1 when
the USB device is in suspend state.
0: Not suspended
1: Suspended
Value after local host or USB reset is low.
13.2.9.4
Configured State (CFG)
Device is attached to the USB and powered, has been reset, has a unique
address, and is configured. The host can now use the function provided by the
device. This bit returns 1 when the USB device has been configured after a set
Dev_Cfg = 1. This bit remains set to 1 until the device becomes deconfigured.
This bit is cleared when the core receives a valid SET_CONFIGURATION
request and the local host sets Clr_Cfg bit. While this bit is not set to 1, any
transaction not for control EP0 is ignored. A GET_ENDPOINT_STATUS to a
non-control endpoint is stalled.
0: Not configured
1: Configured
Value after local host or USB reset is low.