CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
292
(9) UF0 EP status 1 register (UF0EPS1)
This register indicates the USB bus status and the presence or absence of register data.
This register is read-only, in 8-bit units.
RSUM
UF0EPS1
0
5
0
0
3
0
2
0
1
0
0
Address
FF68H
After reset
00H
0
4
6
7
Bit position
Bit name
Function
7
RSUM
This bit indicates that the USB bus is in the Resume status. This bit is meaningful only
when an interrupt request is generated.
1: Suspend status
0: Resume status (default value)
Because sampling is internally performed with the clock, the operation is guaranteed
only when CLK is supplied. Care must be exercised when CLK of the system is stopped.
The INTRSUM signal of SIE operates even when CLK is stopped. It can therefore be
supported by making the RSUMIF bit of interrupt request flag register 1L (IF1L) valid or
lowering the frequency of CLK to the USBF.
This bit is automatically cleared to 0 when it is read.
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