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9.4.6 USB HUB Interrupt Register 0 (HIR0)
Advance Information
128
Address:
$0059
Bit 7
6
Read:
TXDF
RXDF
Write:
Reset:
0
0
= Unimplemented
Figure 9-7. USB HUB Interrupt Register 0 (HIR0)
TXDF — HUB Endpoint 0 Data Transmit Flag
This read only bit is set after the data stored in HUB Endpoint 0
transmit buffers has been sent and an ACK handshake packet from
the host is received. Once the next set of data is ready in the transmit
buffers, software must clear this flag by writing a logic 1 to the TXDFR
bit. To enable the next data packet transmission, TXE must also be
set. If TXDF bit is not cleared, a NAK handshake will be returned in
the next IN transaction.
Reset clears this bit. Writing to TXDF has no effect.
1 = Transmit on HUB Endpoint 0 has occurred
0 = Transmit on HUB Endpoint 0 has not occurred
RXDF — HUB Endpoint 0 Data Receive Flag
This read only bit is set after the USB HUB function has received a
data packet and responded with an ACK handshake packet. Software
must clear this flag by writing a logic 1 to the RXDFR bit after all of the
received data has been read. Software must also set RXE bit to one
to enable the next data packet reception. If RXDF bit is not cleared, a
NAK handshake will be returned in the next OUT transaction.
Reset clears this bit. Writing to RXDF has no effect.
1 = Receive on HUB Endpoint 0 has occurred
0 = Receive on HUB Endpoint 0 has not occurred
5
4
3
0
0
TXDIE
0
0
0
MC68HC(7)08KH12
2
1
Bit 0
0
0
RXDIE
TXDFR
RXDFR
0
0
0
Rev. 1.1
—
Freescale Semiconductor
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