Creating a digital output hangs on the Raspberry Pi 4

[nebrius]

So here's a strange one for you @fivdi. Creating a digital output on the Raspberry Pi 4 hangs.

Environment:

• Raspberry Pi 4 Model B 2GB (hardware revision b03111)
• Node.js 10.16.0 (installed from NodeSource's PPA)
• OS 2019-06-20-raspbian-buster-lite
• pigpio v1.2.3

Code:

const { Gpio } = require('pigpio');

new Gpio(17, {
  mode: Gpio.OUTPUT,
  pullUpDown: Gpio.PUD_OFF
});
console.log('done');

When I run this code, "done" is never printed, and a breakpoint set on that line is never triggered. In addition, when I ctrl+c out of the program, I get sigHandler: Unhandled signal 2, terminating, which implies something is blocking the event loop to me.

Here's the funny bit: when I run this on a Raspberry Pi 3 Model B+ (hardware revision ) with the exact same code, Node.js version, pigpio version, and OS+updates, it works fine.

Note: I did install Raspi IO first, which means the device was configured for Raspi IO (I2C was enabled and certain parameters were set, etc.).

[fivdi]

Hey @nebrius, I hope all is well with you.

The 2019-06-20-raspbian-buster and 2019-07-10-raspbian-buster images come with V68 of the pigpio C library preinstalled which doesn't support the Raspberry Pi 4. The pigpio Node.js module depends on the pigpio C library. Run the command pigpiod -v to see which version of pigpio C library is installed.

V70 of the pigpio C library provides experimental support for the Raspberry Pi 4. The instructions for installing V70 of the pigpio C library can be found at http://abyz.me.uk/rpi/pigpio/download.html.

Please install V70 of the pigpio C library and give it a try. It should be a lot better than V68.

After installing V70 of the pigpio C library a reboot may be required to get the command pigpiod -v to function correctly.

The corresponding pigpio C library issue is joan2937/pigpio#278

when I ctrl+c out of the program, I get sigHandler: Unhandled signal 2, terminating, which implies something is blocking the event loop to me.

This message comes from the pigpio C library either here or here.

Here's the funny bit: when I run this on a Raspberry Pi 3 Model B+ (hardware revision ) with the exact same code, Node.js version, pigpio version, and OS+updates, it works fine.

Compared to previous versions of the Pi, the hardware peripherals on the Pi 4 have changed quite a bit. The pigpio C library therefore needs to be modified accordingly.

Note: I did install Raspi IO first, which means the device was configured for Raspi IO (I2C was enabled and certain parameters were set, etc.).

This shouldn't be an issue.

[cinderblock]

I just ran into this issue as well.

Interestingly, this also launched a daemon on port 8888 when running on Pi4. I was very confused until I found this issue.

Will try to update to V70 and give that a shot. V70 seems to be working so far.

[nebrius]

Thanks for all the info @fivdi, this is helpful.

Compared to previous versions of the Pi, the hardware peripherals on the Pi 4 have changed quite a bit. The pigpio C library therefore needs to be modified accordingly.

Interesting, I'll have to dig in when I have some free time (in September 😅)

[fivdi]

Like the pigpio C library the pigpio Node.js module now has experimental support for the Raspberry Pi 4. Please note that hardware PWM is a little different on the Raspberry Pi 4. For further details see the New & Updates section of the README. The integration tests for the Node.js pigpio module all run successfully on a Raspberry Pi 4.