Altera Cyclone V Device Handbook page 813

cv_54016
2013.12.30
When the DMAC detects a lockup, it signals an interrupt and can also abort the contributing channels. The
DMAC behavior depends on the state of the wd_irq_only bit in the WD register, if:
• wd_irq_only=0 The DMAC aborts all of the contributing DMA channels and sets the irq_abort
signal high.
• wd_irq_only=1 The DMAC sets the irq_abort signal high.
Related Information
Resource Sharing Between DMA Channels
Abort Handling
The architecture of the DMAC is not designed to recover from an abort. You must use an external agent,
such as a microprocessor, to terminate a thread when an abort occurs.
The following figure shows the operating states for the DMA channel and DMA manager threads after an
abort occurs.
Figure 16-4: Abort Process
DMA Controller
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DMA Channel Thread
Executing
Program Thread
Has an Abort
no
Occurred?
yes
Thread Moves to the
Faulting Completing State
no Active AXI
Transactions Complete?
yes
Thread Moves to the
Faulting State
no DMAKILL
Executed?
yes
Thread Moves to the Stopped State
DMA Manager Thread
Executing
Program Thread
Has an Abort
no
Occurred?
yes
16-17
Abort Handling
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