Teensyduino 1.49 Beta #4

[joi]

Try adding this at the beginning of setup()?

  pinMode(A1, INPUT_DISABLE);

Does it help?

This did the trick indeed! Thank you Paul.

j.

[bicycleguy]

This did the trick indeed! Thank you Paul.

j.

Could someone explain why this works. Should the library have set this?

thanks

[defragster]

Could someone explain why this works. Should the library have set this?

thanks

Assuming Paul had an idea to know to suggest this and follow-up is coming. Perhaps a change to be made in pin setup in analog read usage so it just works ...

[Deleted User]

The modification of analog input pin like INPUT_DISABLE, INPUT_PULLUP, etc. before reading should remain possible, because sometimes it may be useful to read a low impedance signal with a pullup attached, for instance to detect a signal failure caused by a crackling potentiometer or a broken connection, etc., while having the easy option to detach the pullup in software so get the best reading.
To define a fixed default behavior would waste this feature altogether and require additional circuits or freaky coding in such use cases.

[defragster]

Could someone explain why this works. Should the library have set this?

thanks

Looking at INPUT_DISABLE it changes the hysteresis handling of the pin. That explains why it was resistant to change mid-value as shown in post #10

		} else { // INPUT_DISABLE
			*(p->pad) = IOMUXC_PAD_DSE(7) | IOMUXC_PAD_HYS;

Something about this passed before - perhaps in the beta - Paul knows … how it gets applied will be forthcoming ...