R01UH0823EJ0100 Rev.1.00
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Jul 31, 2019
RX23W Group
32. USB 2.0 Host/Function Module (USBc)
DTCH Flag (USB Disconnection Detection Interrupt Status Flag)
Indicates the status of the USB disconnection detection interrupt when the host controller is selected.
The USB detects the DTCH interrupt on detecting USB bus disconnection, and sets the DTCH flag to 1. Here, if the
corresponding interrupt enable bit has been set to 1 by software, the USB generates the interrupt.
The USB detects bus disconnection based on USB Specification 2.0.
After detecting the DTCH interrupt, the USB controls hardware as described below (irrespective of the setting of the
corresponding interrupt enable bit). All the pipes in which communications are currently carried out for the USB port
should be terminated by software and make a transition to the wait state for bus connection to the USB port (wait state
for ATTCH interrupt generation).
Modifies the DVSTCTR0.UACT bit for the port in which a DTCH interrupt has been detected to 0.
Puts the port in which a DTCH interrupt has been generated into the idle state.
When the function controller is selected, the read value is invalid.
BCHG Flag (USB Bus Change Interrupt Status Flag)
Indicates the status of the USB bus change interrupt.
The USB detects the BCHG interrupt when a change in the full-speed or low-speed signal level occurs on the USB port
(a change from J-state, K-state, or SE0 to J-state, K-state, or SE0), and sets the BCHG flag to 1. Here, if the
corresponding interrupt enable bit has been set to 1 by software, the USB generates the interrupt.
The USB sets the LNST[1:0] flags to indicate the current input state of the USB port. When the BCHG interrupt is
generated, use software to repeat reading the LNST[1:0] flags until the same value is read three or more times, and
eliminate chattering.
A change in the USB bus state can be detected even while the internal clock supply is stopped.
When the function controller is selected, the read value is invalid.
OVRCR Flag (Overcurrent Input Change Interrupt Status Flag)
Indicates the status of the USB0_OVRCURA and USB0_OVRCURB input pin change interrupt.
The USB detects the OVRCR interrupt when a change (high to low or low to high) occurs in at least one of the input
values to the USB0_OVRCURA and USB0_OVRCURB pins, and sets the OVRCR flag to 1. Here, if the corresponding
interrupt enable bit has been set to 1 by software, the USB generates the interrupt.