MC68HC908LD64 Datasheet, PDF (203/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Universal Serial Bus Module (USB)
Hub Function I/O Registers
14.6.6 USB Hub Interrupt Register 0 (HIR0)
Address: $0059
Bit 7
6
5
4
3
2
1
Read: TXDF RXDF
0
Write:
0
0
TXDIE RXDIE
TXDFR
Reset: 0
0
0
0
0
0
0
= Unimplemented
Figure 14-8. USB Hub Interrupt Register 0 (HIR0)
Bit 0
0
RXDFR
0
TXDF — Hub Endpoint 0 Data Transmit Flag
This read-only bit is set after the data stored in hub endpoint 0
transmit buffers have been sent and an ACK handshake packet
received from the host. 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. TXDF generates an interrupt
request to CPU if the TXDIE bit is also set. Writing to TXDF has no
effect. Reset clears this bit.
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 data
received have been read. To enable the next data packet reception,
RXE must also be set. If RXDF bit is not cleared, a NAK handshake
will be returned in the next OUT transaction. RXDF generates an
interrupt request to CPU if the RXDIE bit is also set. Writing to RXDF
has no effect. Reset clears this bit.
1 = Receive on hub endpoint 0 has occurred
0 = Receive on hub endpoint 0 has not occurred
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
Universal Serial Bus Module (USB)
Data Sheet
203