The DMAC ignores single burst DMA requests.
Note:
<periph>
Sets
bs
to 0 and
p
to 1. This instructs the DMAC to continue executing the DMA channel
thread after it receives a single or burst DMA request. The DMAC sets the
request_type
to:
• Single: When it receives a single DMA request.
• Burst: When it receives a burst DMA request.
Operation
You can only use this instruction in a DMA channel thread.
DMAWMB
Write Memory Barrier forces the DMA channel to wait until all of the executed
DMAST
instructions for that
channel have been issued on the AXI master interface and have completed.
This permits read-after-write sequences to the same address location with no hazards.
Figure 16-24: DMAWMB Instruction Encoding
1
7
6 5 4 3 2 1
0
1
0
0 1
0
0
0
Assembler syntax
DMAWMB
Operation
You can only use this instruction in a DMA channel thread.
Assembler Directives
The assembler provides several additional commands.
DCD
Assembler directive to place a 32-bit immediate in the instruction stream.
Syntax
DCD imm32
DCB
Assembler directive to place an 8-bit immediate in the instruction stream.
Syntax
DCB imm8
DMALP
Assembler directive to insert an iterative loop.
Syntax
DMA Controller
Altera Corporation
cv_54016
DMAWMB
16-42
2013.12.30