Comments on: Raspberry Pi Pico with Interrupts: External and Timer Interrupts (MicroPython)

By: Sara Santos

Sara Santos — Thu, 16 Apr 2026 14:37:04 +0000

Great.
I’m glad you were able to make it work.
Regards,
Sara

By: Bert Oudshoorn

Bert Oudshoorn — Thu, 16 Apr 2026 08:11:32 +0000

Hi Sara,
Apologizes for the confusion. I used a wrong wire. It works correct with even an external 10k pull-down resistor. Thank you very much for your support and the great e-book.

Regards,
Bert

By: Bert Oudshoorn

Bert Oudshoorn — Wed, 15 Apr 2026 11:29:50 +0000

Hi Sara,
Thank you very much for your fast response. Unfortunately, it does not solve the issue (in my case). It looks as if interrupts are stacked, by connecting a resistor (with power… oeps), previous interrupts come through, triggered without the external resistor.
Trying the opposite: FALLING with a PULL_UP does not help. A sad issue.
Regards,
Bert

By: Sara Santos

Sara Santos — Wed, 15 Apr 2026 10:17:54 +0000

In reply to Bert Oudshoorn.

Hi.
This is an issue related to the Raspberry Pi Pico 2 boards.
What happens is that the internal pull-down resistor is disabled.
You need to add a pull-down resistor on the interrupt GPIO (the one the pushbutton is connected to) to your circuit. A 1KOhm resistor will do.
hackaday.com/2024/08/28/hardware-bug-in-raspberry-pis-rp2350-causes-faulty-pull-down-behavior/

Let me know if this fixes the issue.

Regards,
Sara

By: Bert Oudshoorn

Bert Oudshoorn — Wed, 15 Apr 2026 10:09:52 +0000

Hi,
I am trying simple example 4.5.1 and 4.5.2 pushbutton_interrupt (_counter).
The interrupt works only one time…
Using MicroPython firmware 1.28.0 on a RPi-Zero2 via Thonny
It looks as if an interrupt flag is disabled after one call?
Regards, Bert

By: Sara Santos

Sara Santos — Wed, 03 Dec 2025 15:24:48 +0000

In reply to Evan.

Hi.
Thanks for letting me know.
Yes. It seems you’re right. Maybe they stopped supporting that even though they’re still mentioned in the documentation: docs.micropython.org/en/latest/library/machine.Pin.html#machine.Pin.irq

I’ll update the tutorial.

Regards,
Sara

By: Evan

Evan — Mon, 01 Dec 2025 19:24:49 +0000

NB – As of right now this minute – Dec 01, 2025 – the MicroPico extension to VSCode does NOT support IRQ_LOW_LEVEL or IRQ_HIGH_LEVEL conditions when declaring an interrupt service routine for an input pin.

Typing >>> help( machine.pin ) to the REPL lists only IRQ_RISING and IRQ_FALLING.

Whether this is true for Pico MicroPython at large I cannot say. Now that I’ve discovered MicroPico on VSCode I ain’t going back to Thonny ….

Otherwise: These tutorials of yours are simply marvelous! Please keep them coming.

By: Sara Santos

Sara Santos — Sun, 01 Jun 2025 10:15:46 +0000

In reply to Lahcene.

Hi.
The class that we use is called Timer with T. So, when we use Timer, we’re referring to the class.
Regards,
Sara

By: Lahcene

Lahcene — Sat, 31 May 2025 07:43:54 +0000

Hi,
I am a little confused by something in this interesting article.
Sometimes you write Timer with a capital “T” and sometimes with a low “t”. I would like to know where it is required to capitalize the word timer.
Many thanks.
Lahcene

By: Paul

Paul — Thu, 29 May 2025 18:20:13 +0000

Thank you for posting this. Your tutorials are well written and easy to understand.

Please consider doing a tutorial in the future on using the Pico for RS485 half-duplex UART communications. I haven’t been able to locate a “direction” output from the PICO UART to control the direction pin of an RS-485 buffer. Most of Microchip’s AVR microcontrollers include such an output, but I haven’t been able to figure out how to get that from the Pico.

Thank you!