topic Re: MKV5x HSADC sample code in MCUXpresso SDK

MKV5x HSADC sample code

shelbyzhu — Thu, 30 Nov 2017 23:14:39 GMT

We are evaluating TWR-KV58F220M development board so we can upgrade from KV46xx MCU to KV5x MCU.

We installed Xpresso development environment and SDK2.2 for MKV5x (SDK_2.2_TWR-KV58F220M).

We tested a few demo apps and they worked properly. But when we tried HSADC sample from driver_examples folder. The ADC readings did not reflect the input at corresponding ADC input pins.

We tried two boards ordered from different sources and they behave the same. None of them worked. What we saw are constant values (with minor variations) from each channels, eg:

Sample 0 Sample 1 Sample 8 Sample 9

17688 21632 8928 0

16384 21576 208 0

16384 19976 208 8

16384 18592 264 8

16384 18440 240 0

16392 18480 232 0

16392 21608 232 0

16384 20184 208 0

16392 19088 248 8

16384 21624 200 8

16392 19600 200 0

The test input voltage was provided using either GND or 1.5v, with 20k ohm series resistor to the input.

Could anyone help us find out there is anything extra we need to do to get it to work? Or you have updated sample code for us to try?

Regards,

Shelby

Re: MKV5x HSADC sample code

xiangjun_rong — Mon, 04 Dec 2017 06:26:42 GMT

Hi, Shelby,

I think the 20K ohm serial resistor is too large, if you connect the GND or 1.5V to ananlog pin directly, what is the result?

Xiangjun Rong

Re: MKV5x HSADC sample code

shelbyzhu — Mon, 04 Dec 2017 22:50:20 GMT

Hi Xiangjun,

Thanks for helping me on this issue!

I tried connect GND directly to ADC input pin and it did not help. They still show what it would normally show, as if the signal is not connected.

Thanks,

Shelby

Re: MKV5x HSADC sample code

shelbyzhu — Wed, 14 Feb 2018 21:47:02 GMT

When revisiting this, I found that I had connection problems. After the correction, everything worked as expected.

Thanks Xiangjun for the help!

Shelby