LPC553x: ADC hardware trigger sources

[danielholala]

Hi,

according to the manual, ADC hardware triggers can be generated from asynchronous input sources at the periphery of the ADC.

The reference manual reads: "The number and sources of hardware triggers implemented is device-specific. See the chip-specific ADC information for descriptions of available hardware trigger sources for this device."

I could not find the information the manual refers to. 

Where exactly is this "chip-specific ADC information" to be found?

Thanks.

[RaRo · Accepted solution]

Hello @danielholala,

You could check the "chip-specific ADC information" in the Datasheet and/or the User Manual of LPC553x. In this case, you could look the ADC Hardware Trigger information in the LPC553xRM.

For the number and sources of hardware triggers available, please go to:

• Section 46.2.2. Features,

[LPC553xRM. Chapter 46. Analog-to-Digital Converter (ADC)]

• Section 46.1.4. ADC trigger inputs, and

[LPC553xRM. Chapter 46. Analog-to-Digital Converter (ADC)]

• Section 14.5.1.22 and 14.5.1.23. ADCx Trigger input connections.

Best regards, Raul.

[danielholala]

Dear @RaRo ,

as ADC Trigger sources get routed through the Input Multiplexer, I wonder where in Config Tools do I configure these ADC Trigger sources?

Thanks.
Daniel

[RaRo]

Hello @danielholala,

You could configure the ADC and the Trigger Source (e.g. CTimer) with ConfigTools Peripherals.

The INPUTMUX routing could be made through ConfigTools Pins, search for ADC0 -> TRIGx. Select the trigger source number you need and choose the trigger source which would create the INPUTMUX routing in the Code Preview.

[ConfigTools Pins -> INPUTMUX Trigger Sources]

Best regards, Raul.

[danielholala]

Hi @RaRo , 

That's helpful. Thanks. I overlooked the "Peripheral Signals" tab of the Pins Tool.

Cheers
Daniel

[danielholala]

Hello @RaRo ,

Thank you for getting back to me.

Let me please repeat in my own words what I learned from your notes:

Using "INPUTMUXER" registers, I route up to four trigger sources to each ADC (e.g., via registers ADC0_TRIG0 - ADC0_TRIG3 for ADC0) selecting from 35 trigger inputs for each trigger source.

Then using "ADC" registers, for each trigger source that I routed above (up to four), I configure the ADC command that is triggered by that trigger source (e.g., via registers TCTRL0 - TCTRL3).

That's different to the LPC552x with regard to routing trigger sources using the INPUTMUXER is not available on the LPC552x.

Did I understand this correctly?

Cheers,
Daniel

PS: You seem to be looking at a different version of the manual than me. This is what I'm looking at: Rev. 3, 07/2023

https://cache.nxp.com/docs/en/reference-manual/LPC553xRM.pdf

and there the ADC section has been moved to chapter 47:

PPS: If the reference manual could be a bit more elaborate instead of trying to be as concise as possible that would help and I would not need to raise these questions here. Nevertheless, I appreciate all the help I receive through the community forum. Thanks.

[RaRo]

Hello @danielholala,

You are right, we were referring to a different RM of the one you point out. We apologize for the confusion. Please refer to Chapter 46. Analog-to-Digital Converter (ADC). Section 47.2.2. Features and 47.1.6. ADC trigger inputs; and Chapter 14. Input Multiplexing (INPUTMUX). Section 14.5.1.1.20 ADC0 Trigger input connections.

Did I understand this correctly?

Yes, according to the LPC553xRM that is the way to work with ADC trigger inputs.

Best regards, Raul.