[SOLVED] Cambridge Audio Amplifier Control

[Tim Curtis]

It looks like that script is using Broadcom physical pin numbering and not GPIO channel numbering otherwise there would be this line of code 

Code:

# Use SoC pin (GPIO channel) numbering
GPIO.setmode(GPIO.BCM)

so in your command

Code:

python3 ca_amp_ctrl_rpigpio.py --pin 21 ampon

Pin 21 refers to physical pin number 21 on the 40-pin header. This maps to GPIO 9 (MISO). According to the link below GPIO 9 is part of the SPI (Serial Peripheral Interface) and MISO stands for Master In Slave Out.
https://www.tomshardware.com/reviews/ras...,6122.html

I don't know what this means since I don't have much experience with GPIO programming but maybe a pin other than 21 needs to be used?