USB Registers
16.5.5.41 RXGCR9 Register (offset = 928h) [reset = 0h]
RXGCR9 is shown in
and described in
.
Figure 16-192. RXGCR9 Register
31
30
29
28
27
26
25
24
RX_ENABLE
RX_TEARDOWN
RX_PAUSE
Reserved
RX_ERROR_HANDLI
NG
R/W-0h
R/W-0h
R/W-0h
W-0h
23
22
21
20
19
18
17
16
RX_SOP_OFFSET
W-0h
15
14
13
12
11
10
9
8
RX_DEFAULT_DESC_TYPE
RX_DEFAULT_RQ_QMGR
RX_DEFAULT_RQ_QNUM
W-0h
W-0h
W-0h
7
6
5
4
3
2
1
0
RX_DEFAULT_RQ_QNUM
W-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 16-204. RXGCR9 Register Field Descriptions
Bit
Field
Type
Reset
Description
31
RX_ENABLE
R/W
0h
This field enables or disables the channel
0 = channel is disabled
1 = channel is enabled This field will be cleared after a channel
teardown is complete.
30
RX_TEARDOWN
R/W
0h
This field indicates whether or not an Rx teardown operation is
complete.
This field should be cleared when a channel is initialized.
This field will be set after a channel teardown is complete.
29
RX_PAUSE
R/W
0h
Setting this bit causes the CPPI DMA to be suspended for rx
channels.
If a pause is being requested and the channel is not in a packet then
drop the credit.
24
RX_ERROR_HANDLING
W
0h
This bit controls the error handling mode for the channel and is only
used when channel errors (i.e.
descriptor or buffer starvation occurs):
0 = Starvation errors result in dropping packet and reclaiming any
used descriptor or buffer resources back to the original queues/pools
they were allocated to
1 = Starvation errors result in subsequent re-try of the descriptor
allocation operation.
In this mode, the DMA will return to the IDLE state without saving it's
internal operational state back to the internal state RAM and without
issuing an advance operation on the FIFO interface.
This results in the DMA re-initiating the FIFO block transfer at a later
time with the intention that additional free buffers and/or descriptors
will have been added.
Regardless of the value of this bit, the DMA will assert the
cdma_rx_sof_overrun (for SOP) or cdma_rx_mof_overrun (for non-
SOP) when
23-16
RX_SOP_OFFSET
W
0h
This field specifies the number of bytes that are to be skipped in the
SOP buffer before beginning to write the payload.
This value must be less than the minimum size of a buffer in the
system.
Valid values are
0 - 255 bytes.
1978
Universal Serial Bus (USB)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated