CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
390
Figure 12-25. Example of Processing After Power Application/Power Failure (3/3)
(b) Processing on power failure
Yes
INTPx active
Note
?
No
Interrupt servicing
Processing such as
clearing FIFO or
MRST = 1 (UF0GPR)
START
END
Power failure
Note
INTPx means an external interrupt pin of the
µ
PD78F0730 (INTP0 to INTP3).
Allocate one external interrupt pin to the following applications.
•
Detecting disconnection of the connector in the case of self-powered mode (SFPW bit of UF0DSTL
register = 1). In this case, monitor the VDD line of the USB connector, and input the result to the
external interrupt pin at the edge.
•
Detecting turning off power from a HUB chip when the device is mounted on the same board as a
HUB.
Remark
♦
: Processing by hardware
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