I am trying to generate a programmable Bias voltage from 0 to -2V with <0.5mV error.
I was able to generate a programmable positive bias voltage of similar range using DAC. based on this resource .
My idea is to have a negative 5 Voltage supply on the board and connect 0V to 5V, -5V to the ground, So everything is inverted, it will just give me the negative bias voltage with the same accuracy.
However, My problems is that The DAC requires SPI communication from uC which is 3.3 V. I could not talk to the negative section of the board since They are at completely different voltage level.
Is there anyway for me to get around this? Do i have to get another uC on the board just to talk to that DAC?