Looking at several Simplex and Duplex MMDVM “HS Hat’s” I have here that I’m going to change the TCXO to a higher quality part.
I noticed that ALL my boards (Of all different designs) have the TCXO output going to the OSC1 Pin on the ADF7021, but that pin is for using a 0.8V Clipped Sine TCXO output, OSC2 is for a HCMOS/CMOS TCXO with 3V or higher output and all the published schematics and parts lists all list a part number for a TCXO with a 3V or higher (80% of VDD usually) output.
Just curious to why this has been overlooked? Surely to get the most of a high quality TCXO you would use the correct pin on the ADF7021 and disable the internal OSC.
Why are most designs using the wrong TCXO/OSC Pin?
Re: Why are most designs using the wrong TCXO/OSC Pin?
Does anyone know here where the register R1_DB12 is set high or low, is it in the firmware or MMDVM host and what is it set at by default?
Many thanks.
Many thanks.
Re: Why are most designs using the wrong TCXO/OSC Pin?
It will be in the firmware, it's available at github
https://github.com/juribeparada
so you should be able to find how that register bit is set by reading the code.
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Brian G8SEZ
Brian G8SEZ