ADC hardware triggers and results FIFO

[scottm]

I'm having a hard time figuring out how to do anything but the most basic ADC configuration using the SDK. To say the documentation is meager would be an understatement - there's exactly one sentence of explanatory text for the module and it's wrong. (It says it's a 12-bit ADC. On the LPC55S69 it's 16-bit.)

Is there an example somewhere that demonstrates using a hardware trigger and uses the results FIFO? I'm attempting to use a CTIMER as a periodic trigger - previously on Kinetis I had this set up to use the PDB. I can get an interrupt from the CTIMER on its MAT3 output but it's not causing a conversion as far as I can tell.

In this case the sample rate is low and performance isn't critical so it's not a big deal to use a software trigger from a timer, but I'd like to understand the peripheral better before I move on to more critical applications.

Thanks,

Scott

[_Leo_]

Hi @scottm,

Thank you so much for your interest in our products and for using our community.

Could you tell me exactly where 12-bit ADC is specified to report that typo please?

Regarding the ADC examples, the only ones available so far are the following:

Hope it helps you. Please let me know if you have more questions about it.

Have a nice day!

[scottm]

It says it in at least 3 places. See the attached screenshot. Also, it's never explained anywhere what "LPADC" means. The term isn't used in any other NXP documentation as far as I can tell.

My best guess is that there was already an incompatible ADC component in the Kinetis SDK and the LPC version was named LPADC to differentiate it. That's just a guess, though. It's not something I would feel safe assuming, because (for example) there's a Kinetis component called LPTIMER that is a low-power timer and has nothing to do with LPC.

Scott

[_Leo_]

That's correct, in the LPC55S69 documentation it doesn't specify "LPADC", only "16-bit ADC controller (ADC)". Right now I don't have an official answer as to why the name is being changed in the API. But apparently it's because the MCUXpresso SDK API Reference Manual tries to keep everything generic to cover a wide range of microcontrollers. Sorry for the inconvenience. I will report it to the appropriate department. I appreciate your feedback.

[scottm]

Back to my original question, are there any examples or documentation for using hardware triggers with the ADC in the SDK?

Scott

[_Leo_]

As such there is no specific example where only using hardware triggers with the ADC in the SDK for that part. Just the ones I mentioned above.

However, you can refer to the SDK example "mc_pmsm_core0", where the ADCs are triggered from "sct0_output[9]. The user guide for this example is MCUXpresso SDK 3-Phase PMSM Control (LPC) (rev0), which can also be download from MCUXpresso SDK for Motor Control.