• Instruction byte 0 encoding for
DMAGO
.
• Instruction byte 1 encoding for
DMAGO
.
• Debug thread bit to 0 to select the DMA manager thread.
c. Write to the
DBGINST1
register with the
DMAGO
instruction byte [5:2] data. You must set these four
bytes to the address of the first instruction in the program, that is written to system memory in the
step 2 above.
4. Instruct the DMAC to execute the instruction that the debug instruction registers contain by writing
zero to the
DBGCMD
register. The DMAC starts the DMA channel thread and sets the
dbgstatus
bit
to 1. After the DMAC completes execution of the instruction, it clears the
dbgstatus
bit to 0.
Peripheral Request Interface
The following figure shows that the peripheral request interface consists of a peripheral request bus and a
DMAC acknowledge bus that use the prefixes:
•
dr
—The peripheral request bus
•
da
—The DMAC acknowledge bus
Figure 16-3: Request and Acknowledge Buses on the Peripheral Request Interface
DMAC
Peripheral
drvalid
drtype[1:0]
drlast
daready
davalid
datype[1:0]
drready
Peripheral
Request
Interface
The peripheral indicates the following on the request bus:
• Request a single transfer
• Request a burst transfer
• Acknowledge a flush request
The peripheral indicates the DMAC when it issues the last request of the DMA transfer sequence.
The DMAC can indicate the following on the acknowledge bus:
• Indicate when it completes the requested single transfer
• Indicate when it completes the requested burst transfer
• Issue a flush request
You can assign a peripheral request interface to any of the DMA channels. When a DMA channel thread
executes
DMAWFP
, the value programmed in the peripheral [4:0] field specifies the peripheral associated
with that DMA channel.
The DMAC supports 31 peripheral request handshakes. Each request handshake can receive up to four
outstanding requests, and is assigned a specific peripheral device ID. The following table lists the peripheral
device ID assignments.
DMA Controller
Altera Corporation
cv_54016
Peripheral Request Interface
16-10
2013.12.30