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Problem: Pi with PhatDac and pigpio
(10-09-2019, 06:58 PM)TheOldPresbyope Wrote: I've never explored the PCM/PWM capabilities of the RPi boards at the GPIO-pin level, but is it possible you have a collision in GPIO pin usage here? The pHAT DAC apparently interfaces through the physical* pins 2, 12, and 40, which are +5V, BCM 18, and BCM 21. These BCM pins are mapped into I2S usage through the kernel device-tree overlay invoked in the /boot/config.txt file (e.g., dtparam=i2s=on).

I'm wondering if your application might also be exercising BCM 18 and/or BCM 21. (See and click through the pins to see their alternative uses).

Perhaps this could be avoided by using the  -x mask option described in


*not to be confused with WiringPi pin numbers.

Thanks, good idea. But I also checked this before posting here. I'm using BCM14 and 15 for IR transmit and receive, shouldn't lead to any collision of GPIOs as far as I see.
But nice info from you how the overlay maps the pins!

In the meantime I had contact to the pigpio maintainer and the final answer was:

Quote:If you are using waves to generate the IR signal you will not be able
to use either of PWM or PCM for sound.

You will have to find an IR alternative.  Perhaps LIRC or look at one

of the other libraries such as wiringPi or bcm2835.

Even I'm confused about "using waves to generate the IR signal" this means I need an alternative or have to stop the pigpiod if playing sound and vice versa.
Does anyone have experience with wiringPi or bcm2835 fir IR? At the moment I have no idea about both (and no time to try the next 2 weeks).
Maybe it's better to switch back to my unstable solution with LIRC and try to clarify the issues with the lirc maintainer(s)... Confused

Messages In This Thread
Pi with PhatDac and pigpio - by itsme - 10-08-2019, 10:08 PM
RE: Pi with PhatDac and pigpio - by Tim Curtis - 10-08-2019, 11:27 PM
RE: Pi with PhatDac and pigpio - by itsme - 10-09-2019, 11:48 AM
RE: Pi with PhatDac and pigpio - by Tim Curtis - 10-09-2019, 12:10 PM
RE: Pi with PhatDac and pigpio - by itsme - 10-10-2019, 09:15 PM

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