Datasheet

Table Of Contents
Section 15 Universal Serial Bus Interface (USB)
Page 522 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
15.3.28 USB Interrupt Flag Register 1 (UIFR1) (Only in H8S/2215R, H8S/2215T and
H8S/2215C)
UIFR1 is an interrupt flag register indicating the EP2i, EP2o, EP3i, and EP3o. If the
corresponding bit is set to 1, the corresponding EXIRQ0 or EXIRQ1 interrupt is requested from
the CPU. EP2iTR and EP3iTR flags can cleared by writing 0 to them. Writing 1 to them is invalid
and causes no operation. Consequently, to clear only a specific flag it is necessary to write 0 to the
bit corresponding to the flag to be cleared and 1 to all the other bits. (To clear bit 5 only, write
H'DF.) The bit-clear instruction is a read/modify/write instruction. There is a danger that the
wrong bits may be cleared if a new flag is set between the read and write. Therefore, the bit-clear
instruction should not be used to clear bits in this interrupt flag register. However, EP2iEMPTY,
EP2oREDY, EP3oTS and EP3oTF are status bits, and cannot be cleared.
Bit Bit Name Initial Value R/W Description
7
EP3oTF
0
R
EP3o Abnormal Receive
Indicates the status of EP3o FIFO, which can be read
after the next SOF packet has been received following
the data transmission from the host. This flag is set to
1 if a PID error, CRC error, bit staff error, data size
error, or Bad EOP occurs when the data is transferred
from the host to the EP3o. This is a status bit and
cannot be cleared. In addition, an interrupt cannot be
requested by this flag.
6
EP3oTS
0
R
EP3o Normal Receive
Indicates the status of EP3o FIFO, which can be read
after the next SOF packet has been received following
the data transmission from the host. This flag is set to
1 if data is normally transferred from the host to the
EP3o. This is a status bit and cannot be cleared. In
addition, an interrupt cannot be requested by this flag.
5
EP3iTF
0
R/(W)
*
EP3i Abnormal Transfer
Set to 1 if data to be written to the EP3i FIFO is lost
because no IN token has been returned. This flag is
set when the SOF packet that is two packets after the
data write is received. The corresponding interrupt
output is EXIRQ0 or EXIRQ1.
4
EP3iTR
0
R/(W)
*
EP3i Transmit Request
Set to 1 if there is no valid transmit data in the FIFO to
be accessed by the UDC when an IN token is sent
from the host to EP3i. The corresponding interrupt
output is EXIRQ0 or EXIRQ1.