CC2510FX Datasheet, PDF (174/253 Pages) List of Unclassifed Manufacturers – True System-on-Chip with Low Power RF Transceiver and 8051 MCU

CC2510Fx / CC2511Fx
Figure 38 Reading Little/Big Endian
13.15.8 USB Reset
A USB hub may signal reset at any time.
When reset signaling is detected on the
bus, the USB Controller will set
USBCIF.RSTIF and generate an interrupt
if USBCIE.RSTIE is set. The firmware
should take appropriate action when a
USB Reset occurs. A USB Reset would
normally cause the system to be initialized
to a known reset state. The USB function
will typically be reset one or more times
during the enumeration phase right after
the USB cable is connected. A USB Reset
places the device in the default state. In
this state the device will only respond to
address 0 (the default address).
The following actions are performed by the
USB Controller when a USB Reset occurs:
• USBADDR is set to 0
• USBINDEX is set to 0
• All endpoint FIFOs are flushed
• E0CSR, USBCSIL, USBCSIH,
USBCSOL, USBCSOH are cleared.
• All interrupts, except suspend, are
enabled
• An interrupt is generated
Thus, firmware should close all pipes and
wait for a new enumeration phase when
USB Reset is detected.
13.15.9 Suspend and Resume
The USB Controller will enter suspend
mode when the USB bus has been
continuously idle for 3 ms. An interrupt will
be generated if the USBCIE.SUSPENDIE
is set.
While in suspend mode, only limited
current can be sourced from the USB bus.
See the USB 2.0 Specification [2] for
details about this. To be able to meet the
suspend current requirement, the CC2511Fx
should be taken down to PM1 when
suspend is detected. The CC2511Fx should
not enter PM2 or PM3 since this will reset
the USB Controller.
Any valid non-idle signaling on the USB
bus will cause the USB Resume Interrupt
to be generated and wake up the system if
the USB Resume Interrupt is configured
correctly. Refer to 13.15.4.1 for details
about how to set up the USB Resume
Interrupt.
When the system wakes up (enters PM0)
from suspend no USB registers must be
accessed before XOSC has stabilized.
Be aware that the USB Controller will stay
in suspend mode until XOSC has
stabilized and non-idle signaling is
detected on the USB bus. The
USBCIF.RESUMEIF interrupt flag will be
set and a USB Interrupt will be generated
if enabled when the USB Controller exits
from suspend mode.
USB Reset will also wake up the system
from suspend. The USB Resume Interrupt
will be generated, but the USBCIF.RSTIF
interrupt flag will be set instead of the
USBCIF.RESUMEIF interrupt flag.
13.15.10
Remote Wakeup
The USB Controller can resume from
suspend by signaling resume to the USB
hub. Resume is performed by setting
USBPOW.RESUME to 1 for approximately
10 ms. According to the USB 2.0
Specification, the resume signaling must
be present for at least 1 ms and no more
CC2510Fx/CC2511Fx PRELIMINARY Data Sheet (Rev. 1.2) SWRS055A Page 174 of
252