Why is ADC example in SDK has channel 13

[smittal2]

Hi,

I'm looking at the adc_temperature example for QN9080 in MCUXpresso and the ADC channel is defined as 13. How is it possible when the data sheet of QN9080 lists only 8 channels for ADC.

Can someone please explain this?

Thanks,

Sandeep

[mahi · Accepted solution]

Hi Sandeep,

have a look at the user manual https://www.nxp.com/webapp/Download?colCode=UM11023 .

Table 466. ADC input multiplex --> Channel Index 13 = (internal) temperature sensor

Regards
 Martin

[smittal2]

Thanks Marin and Estephania. The document shared by Martin in table 466 made sense to me. I can successfully configure the ADC now. I have a better understanding for the ADC in QN9080 now.

Thanks to you both for your help.

[smittal2]

Hi Estephania/Martin,

I understand that it is temperature sensor. But in the pin config tools it's is routed to ADC4 channel on GPIOA8.

So, I'm confused why the channel is 13 instead of channel 4 if it is using ADC4.

Thanks

[estephania_mart]

Hello,

Please try implementing this without the config tools. The ADC channel 13 it's for the temperature sensor, in that example you will only need to change the pin and channels for the one you want in the ADC initialization.

Regards,

Estephania

[smittal2]

I don't want to use the internal sensor. I want to give an external analog signal using one of the Analog GPIO pins. How can I route a GPIO analog pin to an ADC channel? 

Thanks

[mahi]

That's also written in the manual.

You'll have to set the pin MUX control register 0 (table 29) accordingly --> Pin MUX table (table 95).

You should also have a look at the Pad* registers.

[estephania_mart]

Hello,

Which demo are you using as a reference ?

Regards,

Estephania