preenFM is going to Eurorack

[klangFM]

Attached are two possible desings for scaling an anlog input singal to 3,3V with diode protection.
For a 12 bit convertion it should work. It is easy to implement in existing pcb.

[Xavier]

Thanks Lokki for the feedback and klangFM for the schema.
I forgot to push to github the correct Makefile.
It now compiles fine.

I attached the firmware of this adcIn branch.
USE IT AT YOUR OWN RISK !!! 

For technical info,  a timer interuption and some DMA mechanism sample automatically the 4 analog pins.
It is done 4 times per block for each analog pins.
The final value is the average of those 4 samples to get rid of sample noise.
The final sampling rate is one value per 32 samples so arround 1200Hz. External oscillator as fast as 500Hz should work, wich leads to modulation much faster than the internal lfo.

I only tested with variable resistor pot plugged between 0v and 3.3v as analog source.
So let me know if some of you succed in using real analog hardware.

Xavier


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[klangFM]

Thanks Xavier,
software adcIN  installed and works.
A quick test with hardware scaler on and it works also.
Now test it and play around.
Is it possible to play notes via CV1-FQ and CV2-Gate (routed in matrix)?
At the moment I started to play a note manually or with Midi or running Appegiator.

[Xavier]

Is it possible to play notes via CV1-FQ and CV2-Gate (routed in matrix)?

No. I know this would be great.
Don't know when i'll find time to do that.

Xavier

[klangFM]

Yes,
but at the moment it is great to have the option of CV in.
Let us explore the possibilities and be happy.
I modify my frontpanel for 4 CVin and make a little pcb for 4CV protection/scalers next days.
The pcb fits on JP3 and needs only few cables.
I keep you informed.

willi

[Xavier]

I keep you informed.

Thanks 
Looking forward to see how it goes... and your modified front panel.

[klangFM]

preefm2 with CV inputs:
At the moment only 2CV in are active. PCB only a prototyp. Later a little pcb will be finished to fit direct on P3, input of ADC.
Input protection works fine:

[Xavier]

 Nice to see the 4 cv in 
Thanks for sharing....

[solipsvs]

do want!