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TMS570LC4357: unwanted DMA triggering from HW

Jiri Dobry
Expert 1810 points
Part Number: TMS570LC4357


We have found that DMA channel is triggered accidentally from HW trigger.
More request signals are combined to one in logical or block. It is clear. And it is also clear, that it could work properly only when all DMA request signal on peripherals are disabled, expect the wanted one.

Problem is that DMA signals from I2C are enabled in default state (I2CDMACR register). It was been surprise for us and I need to warn others, because usual generic setting is disabled.

And I have one question. Do you have some list which DMA signals are enabled by default? For ex ADC (ADEVDMACR.EV_DMA_EN) is disabled, CAN id disabled (DCANCTL.DE*), SPI is disabled too (SPIINT*.DMAREQEN).




  • 0
    TI__Guru**** 199006 points

    Hi Jiri,

    1. TMS570LC43x Errata: MIBSPI#137  Spurious RX DMA REQ from a Slave mode MIBSPI 

    2. As described in LC43x TRM, you may get an unexpected DMA I2C transmit and receive event: An unexpected DMA transmit event (ICXEVT) and a DMA receive event (ICXRDY) are generated in 10-bit, master transmit, repeat mode. This event occurs soon after the start condition but before the first bit of the address is transmitted. In this event, no DMA activity should be initiated without the slave ACK being received.

    We don't have list which DMA is enabled by default. I will check later.