Texas Instruments AM335 Series Technical Reference Manual

Event
register
(ER/ERH)
Event
enable
register
(EER/EERH)
Event
set
register
(ESR/ESRH)
Chained
event
register
(CER/CERH)
QDMA
event
register
(QER)
64
64
64
64:1 priority encoder
8:1 priority encoder
8
Event queues
Channel mapping
Queue bypass
Parameter
set 0
Parameter
set 1
set 255
Parameter
Parameter
set 254
Transfer request process submit
PaRAM
E63 E0E1
To
TC(S)
From
EDMA3TC0
From
EDMA3TC3
Completion
interface
Completion
detection
Event
trigger
Manual
trigger
Chain
trigger
Completion
interruptdetection
Error
EDMA3CC_INT[7:0]
From peripherals/external events
EDMA3CC_ERRINT
QDMA trigger
Memory
protection
Read/
write to/
from CPU
EDMA3CC_
MPINT
To chained event register (CER/CERH)
0
15
EDMA3
channel
controller
Early completion
Queue 0
0
15
Queue 1
015
Queue 2
015
Queue 3
www.ti.com Functional Description
Figure 11-4. EDMA3 Channel Controller (EDMA3CC) Block Diagram
A trigger event is needed to initiate a transfer. A trigger event may be due to an external event, manual
write to the event set register, or chained event for DMA channels. QDMA channels auto-trigger when a
write to the trigger word that you program occurs on the associated PaRAM set. All such trigger events
are logged into appropriate registers upon recognition.
Once a trigger event is recognized, the appropriate event gets queued in the EDMA3CC event queue. The
assignment of each DMA/QDMA channel to an event queue is programmable. Each queue is 16 events
deep; therefore, you can queue up to 16 events (on a single queue) in the EDMA3CC at a time. Additional
pending events that are mapped to a full queue are queued when the event queue space becomes
available. See Section 11.3.11.
If events on different channels are detected simultaneously, the events are queued based on a fixed
priority arbitration scheme with the DMA channels being higher priority events than the QDMA channels.
Among the two groups of channels, the lowest-numbered channel is the highest priority.
877
SPRUH73H–October 2011–Revised April 2013 Enhanced Direct Memory Access (EDMA)
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Texas Instruments AM335 Series Specifications

General

Brand	Texas Instruments
Model	AM335 Series
Category	Computer Hardware
Language	English