SPI DMA on OMAP-L138

Martin Turon

Other Parts Discussed in Thread: OMAP-L138

Hi,

I'm trying to drive the SPI bus via DMA on the OMAP-L138 ARM. In the manual, it mentions that writing to the SPI will trigger an XEVT which can trigger an EDMA channel transfer. However, it is not clear to me how to map the SPI event to a particular EDMA channel. Is there a sample app or some documentation on how to map SPI0 to CC0 channel 10 for example?

Related to this, there is a sample app in the quickStart called EDMA_ping_pong_armL138. Here, a timer event triggers an EDMA transfer on CC0 channel 10. I understand most of the register settings and see how they purposefully configure the Timer, IRQ, and DMA to run the example, but again it is not clear to me where or what register mapped Timer12 to trigger EDMA events on CC0 channel 10 specifically. How would I for example map Timer12 to trigger EDMA events on CC1 channel 5 for example?

Thanks so much,
m++

over 14 years ago

0 dabuan over 14 years ago

TI__Genius 14545 points

Hi Martin,

Martin Turon said:
However, it is not clear to me how to map the SPI event to a particular EDMA channel

The EMDA3 Events for any given particular peripheral is fixed on a per-chip basis, which means that the user doesn't have to program it, rather just use the look up table as supplied in the OMAP-L138 Data Manual.

Martin Turon said:
How would I for example map Timer12 to trigger EDMA events on CC1 channel 5 for example?

This is fixed in the hardware. Events 1 is associated with channel 1, Event 2 with Channel 2, etc.

0 Martin Turon over 14 years ago in reply to dabuan

Prodigy 225 points

Hi Drew,

Thanks for the response. That is helpful to know. Could you refer me to which manual specifically contains that table? I could find no such information in the OMAP-L138 general reference (where AINTC registers are described), nor the SPI or EDMA manuals.

Regards,

Martin