NEC switch Network Card User Manual


 
CHAPTER 8 USB FUNCTION
Users Manual U12978EJ3V0UD
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(3) Data/handshake packet transmit interrupt (INTUSBST)
Upon EOP detection during data/handshake packet transmission, an interrupt request signal is generated and
an interrupt request flag (USBSTIF) is set.
(4) USB timer overflow interrupt (INTUSBTM)
If the USB timer overflows, an interrupt request signal is generated and an interrupt request flag (USBTMIF) is
set.
(5) USB reset/Resume detection interrupt (INTUSBRE)
This is an interrupt to release the STOP mode.
If transition from J state (logic 0) to K state (logic 1) is detected on the bus, or transition to SE0 is detected, an
interrupt request signal is generated and an interrupt request flag (USBREIF) is set.
Figure 8-24. Timing of INTUSBRE Generation
(a) Period of RESMOD = 0 and Single-ended 0 (SE0) is 3.0
µ
µµ
µ
s or longer (microcontroller operation)
D+ (USBDP)
D- (USBDM)
INTUSBRE
L
3.0 s or longer
3.0 s
µ
µ
(b) Period of RESMOD = 0 and SE0 is shorter than 3.0
µ
µµ
µ
s (microcontroller operation)
D+ (USBDP)
D- (USBDM)
INTUSBRE
L
Shorter than 3.0 s
Not set
µ
(c) RESMOD = 1
Note
D+ (USBDP)
D- (USBDM)
INTUSBRE
L
Set irrespective of SE0 period
Note Do not set RESMOD to 1 during bus idle. Set RESMOD immediately before the STOP instruction.
Remark RESMOD: Bit 2 of data/handshake packet receive mode register (URXMOD)