External voltage reference help

[justinjools]

Hi, I have set up this circuit using LM4040 -10v voltage reference to use with ADC for measuring control voltage input for a digital oscillator design (using design from BHH link below). I have the power and voltage reference circuits working correctly supplying -10V.

I have tested pitch control voltage input from Beatstep Pro controller directly to ADC0 pin on Arduino. This works fine and I get different voltages for each note. But when I send the control voltage directly through the MCP6002 opamp it gets no signal - I'm guessing this is because it requires the -10v VREF to boost the signal.

So this how it should work: CV1 pitch input + -10v VREF through MCP6002 to ADC0.

Can I test just the AREF signal + CV1 pitch attached to ADC0 or will this blow my Arduino?

Do I need to do anything special with Arduino in software?

I have been following this circuit. MCP6002 opamp is used for circuit protection. Thanks. (PS. all the calculations are correct for 3.3v STM32F1 target MCU and I am using Arduino Uno for testing)