Section 20 USB Function Module
Rev. 4.00 Sep. 14, 2005 Page 751 of 982
REJ09B0023-0400
Bit Bit Name
Initial
Value R/W Description
2 EP0oTS 0 R/W EP0o Receive Complete
This bit is set to 1 when endpoint 0 receives data from
the host normally, stores the data in the FIFO buffer,
and returns an ACK handshake to the host.
1 EP0iTR 0 R/W EP0i Transfer Request
This bit is set if there is no valid transmit data in the
FIFO buffer when an IN token for endpoint 0 is
received from the host. A NACK handshake is
returned to the host until data is written to the FIFO
buffer and packet transmission is enabled.
0 EP0iTS 0 R/W EP0i Transmit Complete
This bit is set when data is transmitted to the host
from endpoint 0 and an ACK handshake is returned.
20.3.2 USB Interrupt Flag Register 1 (USBIFR1)
Together with USB interrupt flag registers 0 (USBIFR0) and 2 (USBIFR2), USBIFR1 indicates
interrupt status information required by the application. When an interrupt occurs, the
corresponding bit is set to 1 and an interrupt request is sent to the CPU according to the
combination with USB interrupt enable register 1 (USBIER1). Clearing is performed by writing 0
to the bit to be cleared, and 1 to the other bits. However, VBUSMN is a status bit, and cannot be
cleared.
USBIFR1 is initialized to H'20 by a power-on reset.
Bit Bit Name
Initial
Value R/W Description
7 to 4 All 0 R Reserved
The write value should always be 0.
3 VBUSMN 0 R Status bit for monitoring the status of the VBUS pin.
The status of the VBUS pin is reflected.
0: Disconnected
1: Connected
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