how to do ADC sequencing on the SAMD21?

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Hello all,

 

My group is using the SAMD21 to read voltages from 4 phototransistor for a school project. I've used the ADC on the L21 before, so I thought it would be trivial to separate out the 4 values, but the D21 is missing the SEQSTATUS register that the L21 has.

 

How do I guarantee that if the processor is putting the right values into the right variables? If the thing runs slow enough, can I just assume it won't skip a reading and screw things up? I don't know enough about the MCU to feel comfortable doing that.

 

I guess a ring buffer might help, but I think there would still be the same problem. If the adc skips a value for some reason, the whole thing will be off.

 

Actually, I forgot about the ADC overrun interrupt. Maybe I can still do a counter, but just have the counter increment on the overrun as well as when it reads the value, just to be safe.

 

Any other advice would be greatly appreciated though!