I have a circuit using LM358N and LTC6240 op amps. The supply is 0-5V and I have used a virtual ground circuit, where 2.5V is my reference. I am happy with my filtered and amplified signal and now want to connect it to the external interrupt of a PIC18F4550. I therefore need to transpose my ac signal from -2.5 - +2.5V to 0-5V
I have tried summing 2.5V from a voltage divider with my signal but get a 0V DC output.
I'm quite perplexed as it seems a simple procedure.