IDT DMA Controller
Internal DMA Operation
79RC32438 User Reference Manual
9 - 13
November 4, 2002
Notes
DMA [0..9] Status Register
Figure 9.7 DMA [0..9] Status Register (DMA[0..9]S)
Description:
Abort.
Writing a one to this field causes the DMA controller to abort the current DMA operation if
one is in progress. The aborting of a DMA operation is acknowledged when the H bit in the
DMAxS register is set. When a DMA operation is in the process of being aborted, writes should
not be performed to the DMAxDPTR and DMAxNDPTR registers until the H bit is set.
Aborting a DMA operation may result in an undefined value in the DEVCS and DEVCMD fields of
the descriptor currently being processed. In addition, the associated peripheral may be left in an
undefined state. Therefore, the corresponding peripheral should always be reset following the
abortion of a DMA operation.
1
Initial Value:
Undefined
Read Value:
0x0
Write Effect
Writing a one to this field causes the DMA controller to abort the current DMA operation.
1.
Following the abortion of a memory to memory DMA operation, the DMA holding FIFO may contain undefined data. This data
must be emptied by initiating DMA operations to empty the FIFO.
F
Description:
Finished.
This bit is set when a descriptor with the IOF bit set completes due to a finished event.
Initial Value:
Undefined
Read Value:
Status
Write Effect:
Sticky bi
t
(a sticky bit is set by the hardware and can only be cleared by the CPU)
D
Description:
Done.
This bit is set when a descriptor with the IOD bit set completes due to a done event.
Initial Value:
Undefined
Read Value:
Status
Write Effect:
Sticky bi
t
(a sticky bit is set by the hardware and can only be cleared by the CPU)
C
Description:
Chain.
This bit is set when a descriptor chaining operation takes place.
Initial Value:
Undefined
Read Value:
Status
Write Effect:
Sticky bi
t
(a sticky bit is set by the hardware and can only be cleared by the CPU)
E
Description:
Error.
This bit is set when an error is detected by the DMA during descriptor processing.
Initial Value:
Undefined
D
DMA[0..9]S
0
31
27
0
F
1
1
C
1
E
1
H
1