TMS320F28379D: Simultaneous data acquisition on multiple channels on C2000 launchpad XL TMS320F28379D -- Ver(2.0)

Hi all,

Looking for a working example that successfully perform ADC and then data acquisition on multiple

channels (2 at a time) given the abovementioned system. This is not our first inquiry on this problem

and already have chatted with our friends there Devin Cottier and Joseph Casuga.We really appreciate

their suggestions and thoughts on this. Both Devin and Joseph have suggested that we look into the

two examples: adc_soc_epwm and adc_soc_continuous, both available at

.../device_support/f2837xd/examples/cpu1.

To exactly quote one of really useful Joseph's message from few months ago:

-- "There are several examples too in C2000Ware where you can see how concurrency for ADC conversions work.

One example is suggest for you to look at is "adc_soc_epwm". In this example, it shows you how to configure the

epwm to trigger ADC conversions. Each EPWM has 2 start of conversion (SOC) triggers. You can use these SOC

signals from the epwm to trigger different channels from different ADC modules of the TMS320F28379D for true

concurrent conversion where 2 channels are converting at the same time. In the "adc_soc_epwm" example, only

one ADC module is shown. You can just duplicate the ADC setup to configure the other ADC module you want to

use for concurrent conversion (note that the TMS320F28379D has 4 ADC modules). In this context, 2 ADC modules

have to be running exactly at the same time (same ADCCLK rate and ACQPS for the ADCs that are active) and

conversion is triggered by the same epwm SOC.

There is also another mode where you can convert on different channels on the same ADC but conversion has to

follow the SOC order (e.g. - SOC0 converts first before SOC1 and SOC2 has to convert before SOC1....and so forth),

but this is not concurrent and rather sequential. A good example to look at that illustrates how this is carried out

is "adc_soc_continuous". " --

Also wonderful feedback and suggestions from Devin and to quote one of his messages:

-- "The next step you need to take is to thoroughly read the ADC chapter of the TRM and then run

the workshop lab.  Look at each line in the code and reference against the bit and functional descriptions

in the TRM until you understand why the lab works.  Repeat for the epwm example.

Once you understand both examples, use the hints from my previous post to extend one example

or the other to sample multiple ADCs in parallel. Note that there is also a mini code-snippet example

in the TRM about sampling multiple channels simultaneously that you can refer to."

My colleagues and I have followed closely these suggestions in regard to adc_soc_epwm example

as well as one of the examples (Lab2) from the following multi-day workshop: processors.wiki.ti.com/.../C2000_Multi-Day_Workshop

Lab2: Analog-to-Digital Converter

None of our tries have been successful so far and only detected & achieved data acquisition

through a single channel. The Lab2 example works nicely using sinusoidal data but only

for a single channel. We modified the example's code in order to handle multiple channels

but nothing were detected for more than a single channel.

** I think we are either totally misunderstanding the hardware or quite likely have missed

specifying some very key components in our code. If someone has an example regardless

of how simple or complex it is and willing to share it with us just to try out we would appreciate it.

Any type of ADC example that would do concurrent data acquisition over multiple channels would be

fine. The objective here is to see how such a setup is done. Once we understand the framework

we will continue trying out our understanding for other examples as we continue using the hardware.

The key point here is just understanding not copying someone else's work.

The hardware is relatively new (roughly over a year or so) to all of us involved and plan to use it

extensively over the coming months in conjunction with other processors for a number of radar

and sensing projects we currently have in the pipeline. Therefore it is crucial that we thoroughly

understand it via running different examples over cpu1 and cpu2 exploiting and utilizing all of

of the channels in different ways (sequential, concurrent, parallel, etc.) in order to harness the true

power of the system.

Many thanks,

Saleh, Joel, Glen and other colleagues.