Issue with TeensyLC

[Florian Rau]

Hi luni64,

I have a strange issue with EncoderTool on TeensyLC.

Here's the MWE:

#include <EncoderTool.h>

using namespace EncoderTool;
PolledEncoder enc;

void setup() {
  Serial.begin(9600);
  enc.begin(5, 6, 4, CountMode::half, INPUT_PULLUP);
}

void loop() {
  enc.tick();
  if(enc.valueChanged())
    Serial.println(enc.getValue());
}

On Teensy 3.2 this works perfectly fine: each detent will increment/decrement by 1. On TeensyLC, however, it will keep incrementing like crazy (without turning the encoder) with each iteration of loop() - but only for every other detent. I'm using this encoder. Is there anything that comes to mind?

Cheers!

[luni64]

This looks weird. Unfortunately I'm currently not at home and don't have a LC with me. I'll have a look on Sunday.

[Florian Rau]

Thanks a lot!

[luni64]

I can reproduce this. It looks like there is a bug in the direct read code for the T-LC. I'll have a closer look later. As a quick workaround you can do the following:

Change line 46 in the library file cores.h as shown here:

This disables the direct read code for the T-LC so that it falls back to a standard digitalRead/digitalWrite which works here.
Can you please check if this works for you as well?

[Florian Rau]

Thanks for looking into this! I can confirm that the workaround makes the encoder perform as expected.

[luni64]

Great, I'll look for a permanent solution asap

[Florian Rau]

Thanks for the fix Lutz! It works as expected now.

[luni64]

Great, let me know if you find something else