Cirrus Logic EP93xx - Manual (Page 430)

10-36 DS785UM1
Copyright 2007 Cirrus Logic
DMA Controller
EP93xx User’s Guide
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Definition:
This is the interrupt status register. The register is read to obtain interrupt
status for enabled interrupts. An interrupt is enabled by writing the
corresponding bits in the CONTROL register.
Write this location once to clear the interrupt. (See the Interrupt Register Bit
Descriptions for the bits where this applies.)
Bit Descriptions:
RSVD: Reserved. Unknown During Read.
STALLInt: Indicates channel has stalled. This interrupt is generated
on a Channel State machine transition from MEM_RD
(memory read) or MEM_WR (memory write) to the STALL
state, assuming STALLIntEn set. The interrupt is cleared
by either disabling the channel or by triggering a new
transfer.
DONEInt: Transaction is done. When enabled, this interrupt is set
when all DMA controller transactions complete normally,
as determined by the transfer count/external peripheral
DEOT signal. When a transfer completes, software must
clear the DONE bit before reprogramming the DMA, by
writing either a “0” or “1” to this bit. This must be done
even if the DMA interrupt is disabled. The DMA will ignore
any additional DREQs that it receives from the external
peripheral (if operating in external DMA mode) until the
software clears the DONE interrupt and reprograms the
DMA with new BCRx values.
NFBInt: Indicates that a channels buffer descriptor is free for
update. This interrupt is generated if NFBIntEn is set,
when a transfer begins using the second buffer of the
double-buffer set, thus informing software that it can now
set up the other buffer. The interrupt is cleared by either
disabling the channel or writing a new BCR value to set up
a new buffer descriptor. The interrupt is not generated for
a single-buffer transfer. In software triggered M2M mode,
servicing of the NFB interrupt is dependent on the system
level AHB arbitration since the DMA’s HREQ (AHB
request) may be continuously held high.