Table 11-3. DMA Control Register (DMACTRL) Field Descriptions (continued)
Bit
Field
Value
Description
1
PRIORITYRESET
0
The priority reset bit resets the round-robin state machine when a 1 is written. Service starts
from the first enabled channel. Writes of 0 are ignored and this bit always reads back a 0.
When a 1 is written to this bit, any pending burst transfer completes before resetting the
channel priority machine. If CH1 is configured as a high priority channel, and this bit is
written to while CH1 is servicing a burst, the CH1 burst is completed and then any lower
priority channel burst is also completed (if CH1 interrupted in the middle of a burst), before
the state machine is reset.
In case CH1 is high priority, the
state machine
restarts from CH2 (or the next highest
enabled channel).
0
HARDRESET
0
Writing a 1 to the hard reset bit resets the whole DMA and aborts any current access (similar
to applying a device reset). Writes of 0 are ignored and this bit always reads back a 0.
For a
soft
reset, a bit is provided for each channel to perform a gentler reset. Refer to the
channel control registers.
If the DMA was performing an access to the XINTF and the DMA access was stalled
(XREADY not responding), then a HARDRESET would abort the access. The XINTF access
would only complete if XREADY is released.
When writing to this bit, there is a one cycle delay before it takes effect. Hence at least a
one cycle delay (i.e., a NOP instruction) after writing to this bit should be introduced before
attempting an access to any other DMA register.
Direct Memory Access (DMA) Module
742
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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