A_1022 A_1023 A_1024
B_1023
B_1022
B_1024
D_1023
C_1023
D_1022
C_1022
D_1024
C_1024
...
...
...
...
...
...
...
...
D_2
D_1
D_3
C_2
B_2
A_2
C_1
B_1
A_1
B_3
C_3
A_3
Channel Source
Address (SRC)
D_1
D_2
D_1023
...
D_3
...
D_1022
D_1024
B_1
C_1
A_1
B_2
C_2
A_2
C_1023
B_1023
A_1023
...
...
...
B_3
C_3
A_3
...
...
...
C_1022
B_1022
A_1022
B_1024 C_1024
A_1024
Channel
Destination
Address (DST)
Functional Description
(b) Channel Options Parameter (OPT) Content
31
30
28
27
24
23
22
21
20
19
18
17
16
0
000
0000
0
0
0
1
00
00
PRIV
Reserved
PRIVID
ITCCHEN
TCCHEN
ITCINTEN
TCINTEN
Reserved
TCC
15
12
11
10
8
7
4
3
2
1
0
0000
0
000
0000
1
1
0
0
TCC
TCCMOD
FWID
Reserved
STATIC
SYNCDIM
DAM
SAM
11.3.19.3 Data Sorting Example
Many applications require the use of multiple data arrays; it is often desirable to have the arrays arranged
such that the first elements of each array are adjacent, the second elements are adjacent, and so on.
Often this is not how the data is presented to the device. Either data is transferred via a peripheral with
the data arrays arriving one after the other or the arrays are located in memory with each array occupying
a portion of contiguous memory spaces. For these instances, the EDMA3 can reorganize the data into the
desired format.
shows the data sorting.
To determine the parameter set values, the following need to be considered:
•
ACNT - Program this to be the size in bytes of an element.
•
BCNT - Program this to be the number of elements in a frame.
•
CCNT - Program this to be the number of frames.
•
SRCBIDX - Program this to be the size of the element or ACNT.
•
DSTBIDX - CCNT × ACNT
•
SRCCDX - ACNT × BCNT
•
DSTCIDX - ACNT
The synchronization type needs to be AB-synchronized and the STATIC bit is 0 to allow updates to the
parameter set. It is advised to use normal EDMA3 channels for sorting.
It is not possible to sort this with a single trigger event. Instead, the channel can be programmed to be
chained to itself. After BCNT elements get sorted, intermediate chaining could be used to trigger the
channel again causing the transfer of the next BCNT elements and so on.
shows the
parameter set programming for this transfer, assuming channel 0 and an element size of 4 bytes.
Figure 11-26. Data Sorting Example
922
Enhanced Direct Memory Access (EDMA)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated