[OPI PC plus Analog audio noise crakles]

 OK i've figured out. It was a problem of background loop https://en.m.wikipedia.org/wiki/Ground_l...ectricity)
Amp and opi were on the same power source.
There are many solution but the cheaper and easiest to me was to power the amp (pam8403) with it's own 5v power supply.

[OPI PC plus Analog audio noise crakles]

Hi when I use the orangepi PC plus TRRS audio output (analog), I have some glitches which are linked to the video mouvment.
I've tested the connection between ground and video and it seems that on the left ground pin there is a natural link with video output (50 ohms), is this normal?
my cable is a 4 pole TRRS. I even tested audio with cable directly plug on soldering but same result.

How could I get a clean audio output?

note that the hdmi audio output is clean.
and my speaker system is clean if I plug it on a MP3 player with an audio jack.

 

I use retrorangepi 4.2 which is based upon Armbian v5.54 (default legacy kernel)

[Orange PI zero WiringOP-Zero build]

with something like this ?

Is there any known lib in C for that, it seems very manual.

 

thx for pointing to me that it was a linux classic.

 

Btw it is for controlling a 433 RF emitter

[Orange PI zero WiringOP-Zero build]

waooo, your lib is a great idea. I do not need a special compatibility with wiringPi, but I would like to drive a MCU with serial communication (more basic than spi or i2c), in your function available I don not see somtehing like this

[Orange PI zero WiringOP-Zero build]

Hi, I'm trying to build wiring on my OPIZ

here is the PI:
 

Welcome to ARMBIAN 5.38 stable Debian GNU/Linux 9 (stretch) 4.14.18-sunxi   
System load:   0.41 0.25 0.10      Up time:       1 min        
Memory usage:  9 % of 493MB      IP:            192.168.1.18
CPU temp:      35°C               
Usage of /:    8% of 15G

 

here is the log

 

GPIO Utility
[Link]
/usr/bin/ld: gpio.o: relocation R_ARM_THM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC
gpio.o: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
Makefile:48: recipe for target 'gpio' failed
make: *** [gpio] Error 1

 

I tried to add -fPIC flag in gpio/Makefile with no succes

 

@$(CC) -o $@ $(OBJ) $(LDFLAGS) -fPIC $(LIBS)

 

[Orange PI zero operate RF 433]

Well it seems that the ninjablocks lib works with the OPI, here is a demo.

There was an interrupt problem mentionned in an old archive, maybe it is solved, I will test that as soon as I get my board

[Orange PI zero operate RF 433]

ho ok reading futher I've seen that I could used ATmega328P serial exposed pin (#0 & #1) as done here

* https://oscarliang.com/raspberry-pi-and-arduino-connected-serial-gpio/

* http://thezanshow.com/electronics-tutorials/raspberry-pi/tutorial-37

 

let see if I can use the rx/tx off the OPIZ

[Orange PI zero operate RF 433]

well my explanation was not enough exact

I mean I do not want to plug an arduino to the OPIZ usb (which is what you are talking with /dev/ttyS1), more likely I would like to drive an Atmega328p alone or ideally an attiny85.

I assume the easiest way is with SPI

[Orange PI zero operate RF 433]

Hi I would like to communicate whith an arduino(as receiver) with RF 433.
On a first thought I wanted to use rc-switch lib, do you know if there is a way to use it with the PI zero(transmitter) once I have installed the wiring pi zero?
if not what would be my best choice as library for OPIZ (and arduino as receiver)?

 

As MCU are better choices to drive hardware part, would it be a good idea to interface OPIZ with a ATMEGA328 as a SPI slave which one would drive the 433 RF emitter with the rc-switch lib above? This would be the overkill situation as I'm new to SPI (and OPIZ).

 

thx