Altera cyclone V Technical Reference page 1208

cv_5v4
2016.10.28
Figure 16-32: Unaligned to Aligned Program
The first
DMALD
therefore the program includes an additional
After the first
ance but it requires a larger number of MFIFO buffer entries.
Note: The
MFIFO buffer entry that the DMAC has already allocated to this channel.
This example has a static requirement of four MFIFO buffer entries and a dynamic requirement of four
MFIFO buffer entries.
Unaligned Source Address to Aligned Destination Address with Excess Initial Load
This program is an alternative to that described in Unaligned Source Address to Aligned Destination
Address. The program executes a different sequence of source bursts that might be less efficient, but
requires fewer MFIFO buffer entries.
DMAMOV CCR, SB5 SS64 DB4 DS64
DMAMOV SAR, 0x1004
DMAMOV DAR, 0x4000
DMALD ; shown as a in the figure below
DMAST ; shown as b in the figure below
DMAMOV CCR, SB4 SS64 DB4 DS64
DMALP 14
DMALD ; shown as c and cn in the figure below
DMALPEND
DMAMOV CCR, SB3 SS64 DB4 DS64
DMA Controller
Send Feedback
Unaligned Source Address to Aligned Destination Address with Excess Initial Load
instruction does not load sufficient data to enable the DMAC to execute a
, the subsequent
DMALD
b b
1
8
4 a
c c
0
shown as does not increase the MFIFO buffer usage because it loads four bytes into an
DMALD d
DMAST ; shown as d in the figure below
, prior to the start of the loop.
DMALD
s align with the source burst size. This optimizes the
DMALD
b n
Data for
first DMAST
d
c
Data for
14x DMAST
e
Data for
last DMAST
Data from
DMALD
DMALD
7
a a a a a a a a
a a a a a a a a
a a a a a a a a
b b b b a a a a
1 1 1 1
b b b b b b b b
1 1 1 1 1 1 1
b b b b b b b b
1 1 1 1 1 1 1
b b b b b b b b
1 1 1 1 1 1 1
b b b b b b b b
1 1 1
b b b b b b b b
n n n n n n n
b b b b b b b b
n n n n n n n
b b b b b b b b
n n n n n n n
d d d d b b b b
n n n
DMAST
16-57
and
DMAST
perform‐
b
0
1
1
1
1
n
n
n
n
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