SAM D21 Analog tolerance

Hi there,

Does anyone know what the tolerance of the SAM D21 analog pins are. Can they read values upwards of 5V? 3.3V?

This chip can be found on the SAM D21 mini breakout by Sparkfun.

DD

Analog and digital I/O is 3.3 volts maximum. Anything about 3.3v will damage the processor.

The downside of a faster processor is could be that is runs on a lower voltage. 3.3volt in this case.
So everything I/O is 3.3volt.

Pins can also source/sink less (7-10mA).
Could give problems interfacing many older style sensors.
Make sure you need the speed, and the sensors will work, before you buy.
Leo..

Thank you for helping!

What would be the best way around this problem. Incoming signal is not really sensitive. Therefore, I can just halve it.

Would a voltage divider with equal values be apropriate. If so, are there any values which are better to use than others. And where on the PCB should these voltage dividers be placed? Closer to the processor or source? Again, these are power signals so not top sensitive.

Thanks

Would a voltage divider with equal values be apropriate.

Yes.
That will give you protection until you reach an input of 6V6, anything over that = damage.

are there any values which are better to use than others.

You have a compromise between getting the impedance into the A/D low and not demanding too much current from the sensor. A good compromise is to use two 10K resistors, but it really depends on your sensor.

And where on the PCB should these voltage dividers be placed?

Dosn't matter.

Again, these are power signals so not top sensitive.

Not quite sure what you mean by that.

Hi Grumpy_Mike!

Thanks. You answered all my questions!