Appendix B
SPRUG34 – November 2008
Setting Up a Transfer
The following list provides a quick guide for the typical steps involved in setting up a transfer.
1. Initiating a DMA/QDMA channel:
a. Determine the type of channel (QDMA or DMA) to be used.
b. If using a QDMA channel, program the QDMA channel
n
mapping register (QCHMAP
n
) with the
parameter set number to which the channel maps and the trigger word.
c. If the channel is being used in the context of a shadow region, ensure the DMA region access
enable registers (DRAE/DRAEH) for the region is properly set up to allow read/write accesses to
bits in the event registers and interrupt registers in the shadow region memory map. The
subsequent steps in this process should be done using the respective shadow region registers.
(Shadow region descriptions and usage are provided in
d. Determine the type of triggering used.
i.
If external events are used for triggering (DMA channels), enable the respective event in
EER/EERH by writing into EESR/EESRH.
ii.
If a QDMA channel is used, enable the channel in QEER by writing into QEESR.
e. Queue setup.
i.
If a QDMA channel is used, set up QDMAQNUM to map the channel to the respective event
queue.
ii.
If a DMA channel is used, set up DMAQNUM to map the event to the respective event queue.
2. Parameter set setup: Program the PaRAM set number associated with the channel. Note that if it is a
QDMA channel, the PaRAM entry that is configured as trigger word is written last. Alternatively, enable
the QDMA channel just before the write to the trigger word.
See
for parameter set field setups for different types of transfers. See the sections on
chaining (
) and interrupt completion (
) on how to set up final/intermediate
completion chaining and/or interrupts.
3. Interrupt setup:
a. If working in the context of a shadow region, ensure the relevant bits in DRAE/DRAEH are set.
b. Enable the interrupt in IER/IERH by writing into IESR/IESRH.
c. Ensure that the EDMA3CC completion interrupt is enabled properly in the device interrupt
controller.
d. Set up the interrupt controller properly to receive the expected EDMA3 interrupt.
4. Initiate transfer (this step is highly dependent on the event trigger source):
a. If the source is an external event coming from a peripheral, the peripheral will be enabled to start
generating relevant EDMA3 events that can be latched to the ER transfer.
b. For QDMA events, writes to the trigger word will initiate the transfer.
c. Manually-triggered transfers will be initiated by writes to the event set registers (ESR/ESRH).
d. Chained-trigger events initiate when a previous transfer returns a transfer completion code equal to
the chained channel number.
SPRUG34 – November 2008
Setting Up a Transfer
165
Содержание TMS320DM357
Страница 2: ...2 SPRUG34 November 2008 Submit Documentation Feedback ...
Страница 12: ...List of Tables 12 SPRUG34 November 2008 Submit Documentation Feedback ...
Страница 16: ...Read This First 16 SPRUG34 November 2008 Submit Documentation Feedback ...
Страница 64: ...EDMA3 Architecture 64 SPRUG34 November 2008 Submit Documentation Feedback ...