Registers
669
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Enhanced Direct Memory Access (EDMA3) Controller
17.4.2.5 DMA Channel Registers
The following registers pertain to the 32 DMA channels. The 32 DMA channels consist of registers (with
the exception of DMAQNUM
n
) that each have 32 bits and the bit position of each register matches the
DMA channel number.
The DMA channel registers are accessible via read/writes to the global address range. They are also
accessible via read/writes to the shadow address range. The read/write ability to the registers in the
shadow region is controlled by the DMA region access registers (DRAE
m
). These registers are described
in
and the details for shadow region/global region usage is explained in
17.4.2.5.1 Event Register (ER)
All external events are captured in the event register (ER). The events are latched even when the events
are not enabled. If the event bit corresponding to the latched event is enabled (EER.E
n
= 1), then the
event is evaluated by the EDMA3CC logic for an associated transfer request submission to the transfer
controllers. The event register bits are automatically cleared (ER.E
n
= 0) once the corresponding events
are prioritized and serviced. If ER.E
n
are already set and another event is received on the same
channel/event, then the corresponding event is latched in the event miss register (EMR.E
n
), provided that
the event was enabled (EER.E
n
= 1).
Event
n
can be cleared by the CPU writing a 1 to corresponding event bit in the event clear register
(ECR). The setting of an event is a higher priority relative to clear operations (via hardware or software). If
set and clear conditions occur concurrently, the set condition wins. If the event was previously set, then
EMR would be set since an event is lost. If the event was previously clear, then the event remains set and
is prioritized for submission to the event queues.
The ER is shown in
and described in
.
Figure 17-61. Event Register (ER)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
E31
E30
E29
E28
E27
E26
E25
E24
E23
E22
E21
E20
19
E18
E17
E16
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
E15
E14
E13
E12
E11
E10
E9
E8
E7
E6
E5
E4
E3
E2
E1
E0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
R-0
LEGEND: R = Read only; -
n
= value after reset
Table 17-43. Event Register (ER) Field Descriptions
Bit
Field
Value
Description
31-0
E
n
Event 0-31. Events 0-31 are captured by the EDMA3CC and are latched into ER. The events are set
(E
n
= 1) even when events are disabled (E
n
= 0 in the event enable register, EER).
0
EDMA3CC event is not asserted.
1
EDMA3CC event is asserted. Corresponding DMA event is prioritized versus other pending DMA/QDMA
events for submission to the EDMA3TC.