I wish that the sBitx had used the standard I2C overlays instead of bit-banging. Back when the sBitx first appeared, I was not convinced that the WM8731 codec and the Si5351A could not work together on a Pi-4 connected to the same I2C bus, So I built my own WM8731 module board according to the manufacturer's datasheet and connected it to the Raspberry Pi 4 along with a Si5351 module and had them both working on the same bus. The date sheet also says it can be controlled by the SPI bus or I2C. I used the standard 12.288MHz crystal? on the codec as well and not the 12MHz as used in the sBitx. If I remember correctly, I used a rotary encoder and some python library code to control the Si5351A to change frequency while listening to some internet music coming from the WM8731 headphone output. I didn't detect any problems with either device. I've been tempted to build my own version of the sBitx hardware without bit-banging or other workarounds but I don't want to deal with all the code changes plus I'd get rid of WiringPi as well. IMHO, the correct way to implement the RTC would have been to make it a system device and then have the sBitx software just read the system time. I'm more familiar with programming MCUs then the Raspberry Pi SBC but when I program a MCU, I try to use standard methods and libraries and if a device doesn't work properly, try a different library or device and not reinvent the wheel.?
So now we have a RTC that's not really a system RTC unless you run the sBitx software.
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Jerry Ponko, AC9NM
JerryP