topic Re: MIMXRT1176 LPADC voltage reference scaling in i.MX RT Crossover MCUs

MIMXRT1176 LPADC voltage reference scaling

sergeydanilov — Tue, 14 Dec 2021 06:53:11 GMT

Hello,

I'm considering the RT1176 MCU for our next product (ethernet attached data acquisition)

Could you please help with the following:

The documentation is not very clear about the LPADC voltage reference scaling feature. Is there any additional documentation, maybe an application note with complete feature description of LPADC?

I need to digitize multiple external analog signals, and it will be really useful to have an individual reference voltage setting for each analog input.

In the current documentation I see that CSW (channel scale width) shows that scaling could be not supported on a particular device, or scale control field could be 1 or 6 bits in size.

Could you please help to find more info about that feature? How can I find what devices support 6 bit scale?

Thanks for the help!

Re: MIMXRT1176 LPADC voltage reference scaling

kerryzhou — Wed, 15 Dec 2021 09:17:09 GMT

Hi @sergeydanilov

Thanks for your interest in the NXP MIMXRT product, I would like to provide service for you.

About the RT1170 reference voltage for ADC, please check the following information:

ADC on RT1170 Supports only 1.0-1.8V reference (no support for 3V reference)

NEVERTHELESS ADC inputs can accept higher input voltages utilizing channel scale factor of 30/64. For example: if 3.3V input voltage required then scale factor must be enabled ADC reference must be set to 1.54V (only supported on VREFH).

As my understand, it is just support 1bit scale now, use the CSCALE choose. 6bit still not support.

You can see, it is just one bit:

If you still have question about it, please kindly let me know.

Best Regards,

Kerry

Re: MIMXRT1176 LPADC voltage reference scaling

sergeydanilov — Mon, 27 Dec 2021 14:43:12 GMT

Thanks for an answer!

Mai I ask if there any way to find out what MCUs support variable (6bit) CSCALE ?

Re: MIMXRT1176 LPADC voltage reference scaling

kerryzhou — Tue, 28 Dec 2021 02:46:43 GMT

Hi @sergeydanilov

Until now, I still didn't find other RT chip support 6bit scale, I think it is used for the future new IP consideration, but still no released product until now.

Wish it helps you!

Best Regards,

Kerry