R01UH0823EJ0100 Rev.1.00
Page 859 of 1823
Jul 31, 2019
RX23W Group
32. USB 2.0 Host/Function Module (USBc)
RHST[2:0] Flags (USB Bus Reset Status Flag)
The RHST[2:0] flags indicate the status of the USB bus reset.
When the host controller is selected, the RHST[2:0] flags indicate 100b after the USBRST bit has been set to 1 by
software.
The USB fixes the value of the RHST[2:0] flags when 0 is written to the USBRST bit by software and the USB
completes SE0 driving.
When the function controller is selected, the RHST[2:0] flags indicate 010b (connection while DPRPU = 1) or 001b
(disconnection while DMRPU = 1) when the USB detects the USB bus reset, and a DVST interrupt is generated.
The UACT bit enables operation of the USB bus (controls the SOF packet transmission to the USB bus) when the host
controller is selected.
With this bit set to 1, the USB puts the USB port to the USB-bus enabled state and performs SOF output and data
transmission and reception.
This module starts outputting SOF packets within one frame after 1 has been written to the UACT bit by software.
With this bit set to 0, the USB enters the idle state after outputting SOF packets.
The USB sets the UACT bit to 0 on any of the following conditions.
A DTCH interrupt is detected during communication (while UACT = 1).
An EOFERR interrupt is detected during communication (while UACT = 1).
Writing 1 to this bit should be done at the end of the USB reset processing (writing 0 to the USBRST bit) or at the end of
the resume processing from the suspended state (writing 0 to the RESUME bit).
This bit should be set to 0 if the function controller is selected.
The RESUME bit controls the resume signal output when the host controller is selected.
Setting the RESUME bit to 1 allows the USB to drive the port to the K-state and output the resume signal.
The USB sets the RESUME bit to 1 on detecting the remote wakeup signal while RWUPE is 1 in the USB suspended
state.
The USB continues outputting K-state while the RESUME bit = 1 (until the RESUME bit is set to 0 by software). The
RESUME bit should be 1 (= resume period) for the time defined by USB Specification 2.0.
This bit should be set to 1 in the suspended state.
Write 1 to the UACT bit simultaneously with the end of the resume processing (writing 0 to the RESUME bit).
This bit should be set to 0 if the function controller is selected.
USBRST Bit (USB Bus Reset Output)
The USBRST bit controls the USB bus reset signal output when the host controller is selected.
When the host controller is selected, setting this bit to 1 allows the USB to drive SE0 of the USB port to reset the USB
bus.
The USB continues outputting SE0 while USBRST = 1 (until the USBRST bit is set to 1 by software). The USBRST bit
should be 1 (= USB bus reset period) for the time defined by USB Specification 2.0.
Writing 1 to this bit during communication (the UACT bit = 1) or during the resume processing (the RESUME bit = 1)
prevents the USB from starting the USB bus reset processing until both the UACT and RESUME bits become 0.
Write 1 to the UACT bit simultaneously with the end of the USB bus reset processing (writing 0 to the USBRST bit).
This bit should be set to 0 if the function controller is selected.