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MSP432 DMA

Pascal4275
Expert 2045 points


Hello!

I'm looking for info about DMA. I have MSP432P401 datasheet and also the 432 user guyde.
The datasheet says that there is a 8-channel DMA.
The user guide sems to agree, (fig 9.1). There are 8 channels with 8 possible sources each.
Now when I look at the DMA in the debugger (registers tab), and if I unfold the DMA
label, I can see 32 channels labeled DMA_CHxx_SRCCFG where xx goes from 0 to 31.


Questions:
1. are there 8 or 32 channels? Or is this a bug of the interface?
2. In the debugger, register dab, I can see 32 channekls sources configurations,
Aren't there destination configurations?
3. I don't see any DMA related source code in what I have downloaded. Are there
sanmple programs somewhere? Or someWare?

Thanks,

Pascal

  • 0
    TI__Guru 68111 points

    Pascal,
    1. There are 8 channels in this device. The TRM is intended to describe a family of products and therefore future products could potentially have up to 32. I hope that makes sense. Additionally, you can look at the contents of the DMA_DEVICE_CFG register and see that there are 8 sources per channel and 8 channels.
    2. The 32 possible channels are shown in the 32 possible registers. In this device only 8 are in use. If you refer to table 6-8 in the datasheet (www.ti.com/.../msp432p401r.pdf) your will see the map of DMA sources and channels. For example the ADC is only available on channel 7 and is denoted by SRCCFG=7, so this is written to DMA_CH7_SRCCFG register to connect the ADC trigger to the channel 7 DMA input.
    3. The DMA example code is provided in the context of driverLib. (dev.ti.com/.../

    Let me know if you have additional questions.

    Chris

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