MK20 single ended ADC B channels

[kbhadane]

Hello, 

We are using MK20DX256 and as we are using all the ADC channels, we have wired up a new product using the B channel of the ADCs.  But we find that we can not start the Conversion process.  We have verified that the they are configured correctly. There are reference in the Reference Manual (November 2011) that suggest that these "B" type ADCs might require some kind of external trigger on a pin named ADHWT and ADHWTS.   But we can not find any reference to pins or registers with that designation.   In the application note linked below, we have also seen reference to triggering the ADC with PDB, but there was no clear explanation on how to start the trigger (from within software) using that method.  Can you provide us with Sample Code that initializes a B-channel ADC, initiates the Conversion, and then reads back the value?

https://www.nxp.com/docs/en/supporting-information/Analog-to-digital-Converter-Training.pdf

Thank you!

[kbhadane]

Hello Kerry, 

We are using MK20DX256VLK10. We aren't planning to use DMA. We are using software trigger for rest of the channels. Here are few questions I have,

  1) As all channel B need hardware trigger, is there any way I can trigger the channel B without any hardware modifications? e.g. using FTM channel or just PDB for triggering? What are the options?

2) We are using software trigger for other channels and we don't want to use DMA, how can I configure channel B to be triggered using hardware trigger for single shot. We are using ADC1_SE4B, ADC1_SE5B, ADC1_SE6B, ADC1_SE7B in our project. 

It would be really helpful if you can provide a sample code and information on how to use channel b. 

Thank you,

Kunal

[kerryzhou]

Hi Kunal Bhadane,

  I have a question, why you don't  use the channel A? Channel can be used both the software and hardware trigger.

  You can don't use the DMA, just the other module hardware trigger.

  Anyway, I will checking the 100M related code, if I find it, I will share it with you.

Best Regards,

Kerry

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[kerryzhou]

Hi Kunal Bhadane, 

  Please also let us know your detailed K20 chip part number, as K20 has a lot of series. 100Mhz, 72Mhz, 50Mhz.

 About the ADC SC1B with PDB, you also can refer to this post:

https://community.nxp.com/message/347622?commentID=347622#comment-347622 

  There has some code sharing for your reference.

Wish it helps you!

Best Regards,

Kerry

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