Specifications

V850E2/MN4 USB CDC (Communication Device Class) Driver
R01AN0010EJ0101 Rev.1.01 Page 27 of 117
Feb 01, 2012
4.2.3 USBF Interrupt Processing (INTUSFA0I1)
Of the interrupt requests (INTUSFA0I1) from the USB function controller, only those for which the interrupt mask has
been cleared at initialization are reported. Therefore applications must clear the interrupt masks at initialization for all
required interrupts. For all reported interrupts, the corresponding required processing will be performed.
Start of INTUSFA0I1
interrupt processing
RSUSPD interrupt processing
BUSRST interrupt processing
SETRQ interrupt processing
CPUDEC interrupt processing
BKO1DT interrupt processing
End of INTUSFA0I1
interrupt processing
Figure 4.5 INTUSFA0I1 Interrupt Handler Processing Flow
(1)
RSUSPD Interrupt Processing
If the RSUSPD bit in the USFA0IS0 register is 1, the RSUSPDC bit in the USFA0IC0 register will be cleared to 0.
Next, if the RSUM bit in the USFA0EPS1 register is 1, the flag that indicates the suspend state (usbf850_rsuspd_flg)
will be updated (a suspend will occur).
(2)
BUSRST Interrupt Processing
If the BUSRST bit in the USFA0IS0 register is 1, the BUSRSTC bit in the USFA0IC0 register will be cleared to 0.
Next, the flag that indicates that a bus reset has occurred (usbf850_busrst_flg) is updated (a bus reset occurred), the
function usbf850_buff_init() is called and the buffer is initialized.