Setting DMA with ADC in F28335 (2018a/2020b)

Hello,

I am in the second round configuring DMA with ADC in F28335 with TI C2000 support package. Now I am using Matlab 2020b. I am struggling with the memory allocation definitions in Simulink.

I need DMA ch1 to transfer the data adquired by ADC to an user defined memory allocation. I have 10 channels, so I have configured it for a Burst size of (10-1). I'm using a Data store and Memory allocation blocks to access stored data as in Matlab example c28x7x_c28004x_dma_epwm

My Burst source address is the ADC register (following controlsuite examples): &AdcMirror.ADCRESULT0

My Burst destination address is a buffer ADCbuffer[10], so I set: &ADCbuffer[0]

If I define ADCbuffer in Simulink environment, I mean, Model properties/Callbacks, or even in Model explorer/Model environment as a Simulink.signal, I find that the compiler gives an error in DMA configuration because ADCbuffer is not defined.

However, if I define it in a custom header in Configuration parameters/Custom code, as (taken from controlsuite/adc_dma example):

#pragma DATA_SECTION(ADCbuffer,"DMARAML4");
volatile Uint16 ADCbuffer[10];

Now I get that ADCbuffer is defined in all .obj files...

Other setups gave me catastrophic errors...

The example c28x7x_c28004x_dma_epwm sets the Burst source address as duty_cycle_table, a signal generated by executing "sineTableCalculation" comand in Model properties/Callbacks, at InitFcn as well as at PreLoadFcn.

So I would be really grateful to get some advice:

• Where should I define the DMA buffer?
• It is needed a specific variable type?
• Additional tips to take into account?

Thank you for your time.

[Venkatesh Chilapur]

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Regards,

Venkatesh C