SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Several of the 64 DMA channels are tied to a specific hardware event, thus allowing events from device peripherals or external hardware (via the dma_evt[4:1] pins) to trigger transfers. A DMA channel typically requests a data transfer when it receives its event (apart from manually-triggered, chain-triggered, and other transfers). The amount of data transferred per synchronization event depends on the channel’s configuration (EDMA_TPCC_ABCNT_n[15:0] ACNT, EDMA_TPCC_ABCNT_n[31:16] BCNT, EDMA_TPCC_CCNT_n[15:0] CCNT, etc.) and the synchronization type (A-synchronized or AB-synchronized).
The association of an event to a channel is fixed within the EDMA Channel Controller, that is, each DMA channel has one specific event associated with it. The EDMA event crossbar can be used to select which level events (of which there are more than 64) are mapped to the 64 input events to the EDMA Channel Controller. The default mapping and event crossbar mapping are defined in Section 16.2.3.1, EDMA Requests to the EDMA Controller. The event crossbar mapping is controlled by the device Control Modules registers refer to IRQ_CROSSBAR Module Functional Description, in Control Module.
In an application, if a channel does not use the associated synchronization event or if it does not have an associated synchronization event (unused), that channel can be used for manually-triggered or chained-triggered transfers, for linking/reloading, or as a QDMA channel.