Nuvoton NUC502ADN User Manual

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Nuvoton NUC502ADN User Manual Manual pdf 93 page image

NUC502Apr 30, 2015 Page 93 of 266 Rev 1.16.7.3.5 InterruptThis USB provides 1 interrupt source with 4 interrupt events (WAKEUP, FLO, USB, BUS).WAKEUP interrupt is for stop wakeup only, FLO interrupt is for USB plug-in or unplug, USBevent notifies users of some USB requests, like IN ACK, OUT ACK etc., and BUS eventnotifies users of some bus events, like suspend, resume, etc. User must enable both AICand IEF of USB to enable USB interrupts.Wakeup interrupt is only present after stop wakeup. After the IC enters power downmode, any change on D+, D- and floating detect pin can wake up NUC502 (provided thatUSB wakeup function is enabled). If this change is not desired, for example, a noise onfloating detect pin, no interrupt but wakeup interrupt will occur. After USB wakeup, thisinterrupt will occur when no other USB interrupt events are present for more than 20mS.USB interrupt is to notify users of any USB event on the bus, and a user can read SFR“STSX” and “EPTF” to acknowledge what kind of request is to which endpoint and takenecessary responses.Same as USB interrupt, BUS interrupt notifies users of some bus events, like USB reset,suspend, timeout, and resume. A user can read SFR “ATTR” to acknowledge bus events.6.7.3.6 Power SavingUSB turns off PHY automatically to save power while NUC502 enter power down mode.Furthermore, a user can write 0 into SFT ATTR[4] to turn off PHY under specialcircumstances like suspend to save power.6.7.4 Memory MappingAddress Size Type DescriptionUSB_BA +(000h ~ 0FFh)256 Bytes Register Special function registerUSB_BA +(100h ~ 1FFh)256 Bytes SRAM USB buffer6.7.5 USB Control Registers MappingRegister Address R/W Description Reset ValueUSB_BA = 0xB100_9000IEF USB_BA+0x000 R/W Interrupt Enable Flag 0x0000_0000EVF USB_BA+0x004 R Interrupt Event Flag 0x0000_0000FADDR USB_BA+0x008 R/W Function Address 0x0000_0000STS USB_BA+0x00C R, W System state 0x0000_00x0ATTR USB_BA+0x010 R/W Bus state & attribution 0x0000_0040FLODET USB_BA+0x014 R Floating detect 0x0000_0000