SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Table 24-359 shows the configuration of the McASP using the DMA method for transmission. Possible interrupt error event servicing is also considered. Table 24-358 shows the initial setup for DMA - based transmission.
Because of the DATA port burst access capability with the DMA method, it is strongly recommended that DMA transfers are initiated through the McASP DATA port.
Step | Register/Bit Field/Programming Model | Value |
---|---|---|
Recommended: Select DATA port to access the transmit buffers. | MCASP_TXFMT[3] XBUSEL | 0x0 |
Enable the Tx DMA requests generation. | MCASP_XEVTCTL[0] XDATDMA | 0x0 |
Enable the Tx DMA error event, because of McASP DATA port usage. | MCASP_EVTCTLX[3] XDMAERR | 0x1 |
Optional: Enable the transmit error event interrupts. | MCASP_EVTCTLX[2] XCKFAIL MCASP_EVTCTLX[1] XSYNCERR MCASP_EVTCTLX[0] XUNDRN | 0x1 0x1 0x1 |
Optional: Enable the start of frame interrupt. Optional: Enable the last slot data interrupt. | MCASP_EVTCTLX [7] XSTAFRM MCASP_EVTCTLX[4] XLAST | 0x1 0x1 |
Disable the data ready event transmit interrupt, as DMA is used to service this request. | MCASP_EVTCTLX[5] XDATA | 0x0 |
DMA startup transmission procedure. This procedure is identical than the one shown in Figure 24-136. The only difference is that DMA automatically services all the AXEVT events raised by the McASP, and no CPU data processing intervention is required. The CPU is involved only in error handling shown in Figure 24-139. | See Figure 24-136. |