Motorola PowerQUICC II MPC8280 Series Reference Manual page 878

USB Host Description
Table 27-11. USEPx Field Descriptions (continued)
Bits Name
10 MF Enable multi-frame. For USB function controller
allows loading of the next transmit packet into the
FIFO before transmission completion of the
previous packet.
0 Transmit FIFO may hold only one packet
1 Transmit FIFO may hold more than one packet
Note: For USB function configuration: Should be
cleared unless the endpoint is configured for ISO
transfer mode.
11 RTE Retransmit enable for USB function controller
0 No retransmission
1 Automatic frame retransmission is enabled. The
frame will be retransmitted if transmit error
occurred (time-out).
Note: May be set only if the transmit packet is
contained in a single buffer. If it is not,
retransmission should be handled by software
intervention.
Note: Should be set to zero for endpoint which is
configured for ISO transfer mode
12–13 THS Transmit hand shake for USB function controller.
This field determines the response to an IN
transaction.
00 Normal handshake
01 Ignore IN token
10 Force NACK handshake. Not allowed for control
endpoint.
11 Force STALL handshake. On a control endpoint
this value is used to generate a protocol stall; in
this case THS will be cleared by the USB
function controller when a SETUP token is
received.
14–15 RHS Receive hand shake for USB function controller.
This field determines the response to an OUT
transaction.
00 Normal handshake
01 Ignore OUT token
10 Force NACK handshake and discard the data.
This value may be used for flow control. Not
allowed for control endpoint.
11 Force STALL handshake. On a control endpoint
this value is used to generate a protocol stall; in
this case RHS will be cleared by the USB
function controller when a SETUP token is
received.
27.5.7.4 USB Command Register (USCOM)
USCOM is used to start the USB transmit operation.
27-20
Freescale Semiconductor, Inc.
USB Function Mode
MPC8280 PowerQUICC II Family Reference Manual
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USB Host Mode
Enable multi-frame for USB host controller. Should
be always set.
Transaction-level interface for USB host controller.
0 Packet-level interface as described in
Section 27.5.1.1, "Packet-Level Interface."
1 Transaction-level interface as described in
Section 27.5.1.2, "Transaction-Level Interface."
Transmit hand shake for USB host controller
00 Normal handshake
Receive hand shake for USB host controller
00 Normal handshake
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