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AM6546: External DMA trigger pins

DJ-NG
Genius 9355 points
Part Number: AM6546

Hi champs,

customer  has much experience with AM335x and uses external DMA trigger from an external ASIC for data R/W transfers between MPU and ASIC.

ASIC is master.

In AM65x he misses obvious similar DMA trigger capabilities, which is important for migration to this platform.

Q: Is HW triggered (pins) DMA request from external implemented in AM65x? Pls explain!

  • 0
    TI__Guru* 87040 points

    Hi DJ,

    yes, this can be implemented, just the routing of the external DMA event has to be configured.    You would use the Time Sync Router (see section 11.3.2) to route external pins to a DMA event.   

    Refer to Figure 11-56 in the TRM.  You can use either CPTS_HWnTSPUSH signals (shown as CPTS_HWnPUSH in the diagram), or the MCU_CPTS_HWnTSPUSH (shown as MCU_CPTS_HWnPUSH in the diagram).  Note that in the diagram, there are also other external signals directly connected to the Time Sync Router that you could use.  If you look in table 11-184, you can see SYNCEVENT32_INTRTR_IN32 corresponds to CPTS_HW1TSPUSH signal, and so on.  These are how the input events map to each of the inputs.

    On the output side, there are several outputs from the Time Sync Router, some of which go to PDMA1 (see "DMA Local Events" in the figure).    Check table 11-163, which defines the output hardware requests from the Time Sync Router.  Sync events 32-39 corresponds to the ones that go to PDMA1 

    Once the event is in the PDMA1, it can trigger a DMA event.  See Section 10.1 for a description of the DMA architecture

    Regards,

    James