Event
Register
(ER/ERH)
Event
Enable
Register
(EER/EERH)
Event
Trigger
Event
Set
Register
(ESR/ESRH)
Manual
Trigger
Chained
Event
Register
(CER/CERH)
Chain
Trigger
QDMA
Event
Register
(QER)
QDMA Trigger
64
64
64
64:1PriorityEncoder
8:1PriorityEncoder
8
Queue 0
Queue 1
Queue Bypass
15
0
15
0
Event
Queues
ChannelMapping
Parameter
Set 0
Parameter
Set 1
Parameter
Set 126
Parameter
Set 127
PaRAM
T
ransferRequestSubmission
Completion
Detection
Completion
Interface
Completion
Interrupt
Error
Detection
E0
E1
E63
EDMA3 Channel
Controller
From
EDMA3TC0
From
EDMA3TC1
EDMA3CC_ERRINT
EDMA3CC_INT[2:0]
to ARM/IMCOP
From Peripheral/External Events
To
EDMA3TC(s)
www.ti.com
Functional Overview
Figure 2-2. EDMA3 Channel Controller (EDMA3CC) Block Diagram
A trigger event is needed to initiate a transfer. For DMA channels, a trigger event may be due to an
external event, manual write to the event set register, or chained event. QDMA channels are autotriggered
when a write is performed to the user-programmed trigger word. All such trigger events are logged into
appropriate registers upon recognition. Refer to DMA channel registers (
) and QDMA
registers (
Once a trigger event is recognized, the event type/channel is queued in the appropriate EDMA3CC event
queue. The assignment of each DMA/QDMA channel to event queue is programmable. Each queue is
16 deep, so up to 16 events may be queued (on a single queue) in the EDMA3CC at an instant in time.
Additional pending events mapped to a full queue are queued when event queue space becomes
available. Refer to
If events on different channels are detected simultaneously, the events are queued based on fixed priority
arbitration scheme with the DMA channels being higher priority than the QDMA channels. Among the two
groups of channels, the lowest-numbered channel is the highest priority.
Each event in the event queue is processed in the order it was queued. On reaching the head of the
queue, the PaRAM associated with that channel is read to determine the transfer details. The TR
submission logic evaluates the validity of the TR and is responsible for submitting a valid transfer request
(TR) to the appropriate EDMA3TC (based on the event queue to EDMA3TC association, Q0 goes to TC0,
Q1 goes to TC1, etc.). For more details, see
.
The EDMA3TC receives the request and is responsible for data movement as specified in the transfer
request packet (TRP) and other necessary tasks like buffering, ensuring transfers are carried out in an
optimal fashion wherever possible. For more details on EDMA3TC, see
.
SPRUG34 – November 2008
EDMA3 Architecture
23
Содержание TMS320DM357
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