USB Device Controller
1583
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.3.1.16 DMA Receive Channels Configuration Register (RXDMA_CFG)
This read/write register enables the three possible DMA receive channels and selects the endpoint
number that is assigned to each of these DMA channels. An endpoint used by an RX DMA channel must
have been configured (through register EPn_RX). The RXDMA_CFG register can be filled when
SYSCON1.CFG_LOCK is set.
Only one channel is serviced at a time, so it is better to configure ISO endpoints on the first channel
(_EP). If the ISO endpoint is configured on channel 2, it can never be serviced with low software and a
fast USB host.
The USB device controller transmit endpoint DMA channels 0, 1, and 2 are associated with device
controller inputs.
NOTE:
System software must not program RXDMAx_EP to endpoint numbers that are not
configured as DMA endpoints.
Figure 29-43. DMA Receive Channels Configuration Register (RXDMA_CFG)
[address = FCF78A20h]
15
13
12
11
8
Reserved
RX_REQ
RXDMA2_EP
R-0
R/W-0
R/W-0
7
4
3
0
RXDMA1_EP
RXDMA0_EP
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value at reset
Table 29-47. DMA Receive Channels Configuration Register (RXDMA_CFG)
Field Descriptions
Bit
Field
Value
Description
15-13
Reserved
0
Reserved
12
RX_REQ
The RX DMA request active level or pulse bit allows the RXDMA request to be configurable level or
pulse-sensitive. When pulse-sensitive, the request is active during 2 cycles.
0
RX DMA request active level.
1
RX DMA request active pulse.
Value after system reset or USB reset is low.
11-8
RXDMA2_EP
Receive endpoint number for DMA channel 2. The endpoint number binary encoded in these four
bits is the current receive endpoint selected for DMA channel 2. A zero value indicates that the
DMA channel 2 is deactivated. Any other value automatically enables receive DMA transfer for the
selected endpoint.
0
Receive DMA channel 2 is deactivated.
1h
EP1
:
:
Fh
EP15
Values after system reset or USB reset are low (all 4 bits).
7-4
RXDMA1_EP
Receive endpoint number for DMA channel 1. The endpoint number binary encoded in these four
bits is the current receive endpoint selected for DMA channel 1. A zero value indicates that the
DMA channel 1 is deactivated. Any other value automatically enables receive DMA transfer for the
selected endpoint.
0
Receive DMA channel 1 is deactivated.
1h
EP1
:
:
Fh
EP15
Values after system reset or USB reset are low (all 4 bits).