Teensy++, three pins won't go low

[frax]

Hi,

I wanna use the pins called 38-45 (F0-7) on this PDF:
https://www.pjrc.com/teensy/card4b.pdf
as digital output.

pinMode(38, OUTPUT);

and then a simple digitalWrite(38, ... HIGH/LOW blinker works just fine.
38, 39, 40 and 41 all good but 42, 43, 44 and 45 won't go low. They even stay HIGH when I set them as inputs.

Teensy is not connected to anything else.

Is there anything special withe these three pins?

[frax]

Found this which seems to be identical:
https://forum.pjrc.com/threads/56227...-control-PORTF

Could this be a clone? Bought it years ago, don't remeber where. But I have one more Teensy++ which Im sure is not a fake, i'll give that one a try.

[PaulStoffregen]

Is it a genuine Teensy++ 2.0, or maybe a counterfeit? Can you show us a photo of the board?

[frax]

And the suggested
MCUCR = (1<<JTD) | (1<<IVCE) | (0<<PUD);
MCUCR = (1<<JTD) | (0<<IVSEL) | (0<<IVCE) | (0<<PUD);

works perfect, all pins behave as expected now

[frax]

Here's a picture of the apparently fake Teensy.

[PaulStoffregen]

Yup, that's definitely a counterfeit.

If you bought it within the last 90 days, odds are good you'll get your money back with a complaint.

[frax]

Bought it years ago, probably of ebay.