AT83C51SND1C_03 ATMEL [ATMEL Corporation], AT83C51SND1C_03 Datasheet - Page 96

• Manufacturer Part Number: AT83C51SND1C_03
• Description: Single-Chip Flash Microcontroller with MP3 Decoder and Human Interface
• Manufacturer: ATMEL [ATMEL Corporation]

Upstream Resume
Figure 67. Example of REMOTE WAKEUP Management
96
AT8xC51SND1C
SET_FEATURE: DEVICE_REMOTE_WAKEUP
Detection of a SUSPEND state
upstream RESUME sent
A USB device can be allowed by the Host to send an upstream resume for Remote
Wake-up purpose.
W h e n
DEVICE_REMOTE_WAKEUP, the firmware should set to 1 the RMWUPE bit in the
USBCON register to enable this functionality. RMWUPE value should be 0 in the other
cases.
If the device is in SUSPEND mode, the USB controller can send an upstream resume by
clearing first the SPINT bit in the USBINT register and by setting then to 1 the SDRM-
WUP bit in the USBCON register. The USB controller sets to 1 the UPRSM bit in the
USBCON register. All clocks must be enabled first. The Remote Wake is sent only if the
USB bus was in Suspend state for at least 5ms. When the upstream resume is com-
pleted, the UPRSM bit is reset to 0 by hardware. The firmware should then clear the
SDRMWUP bit.
UPRSM = 1
t h e
U S B
SPINT
UPRSM
c o n t r o l l e r
Suspend Management
USB Controller Init
Clear SDRMWUP
Set SDMWUP
Set RMWUPE
enable clocks
Clear SPINT
r e c e i v e s
t h e
need USB resume
S E T _ F E A T U R E
4109E–8051–06/03
r e q u e s t :