Re: mode2 shows output, irrecord fails (using the remote out port of an amplifier)

Hi Bengt,

Am 05.03.20 um 10:29 schrieb Bengt Martensson:
>> I have connected the REMOTE OUT port of my amplifier (Marantz PM5005)
>> with the GPIO pin of my Raspberry Pi¹
> 
> The magic word here is that the remote out plug on Maranz outputs the
> signal *inverted* (signal present = low, no signal = high), so that your
> spaces show up as pulses, and vice versa. This explains the very long
> initial "pulse" you see. Taking this into account, your first signal

Thank you, that makes sense. I saw with Piscope that the signal was
exactly inverted to that of a TSOP I had connected to the Pi for testing
in parallel.


> decodes as  RC5: {D=16,F=16,T=1} in IrScrutinizer.
> 
> Ok, so we know that it is a Marantz amplifier, using RC5 with D=16. So I
> use IrScrutinizer to suck the corresponding device from irdb.tk, and use
> the Lirc-export. Produces the file enclosed.

Thank you. Unfortunately, it does not seem to work. I copied your file
to /etc/lirc/lircd.conf.d/pm5005.lirc.conf, restarted lircd and then run
irw but I get no output. (According to the systemd log lircd uses the
marantz_amp-rc5 remote and irw also connected as a client.)

Is there any way to invert the signal on the software side? The gpio-ir
kernel module in 4.19.66-v7+ apparently does not have a parameter for
that and I could also not find an option in the lirc (0.9.4c) docs. I
know that I could do it in hardware but it would be so much easier in
software (in theory ;-).¹


> BTW, irrecord is a really not state-of-the art. Please use
> IrScrutinizer, which runs natively on the RPi. Although in this case it
> would not have helped you, because the driver for reading GPIO inverted
> is still not written...

Good to know. I have tried irscrutinizer before but I have always
received an OddSequenceLengthException.



Best,
Robert


¹ I would rather patch the driver or lirc than solder.