You will get a knock code. But that can be wired in to. What ecu are you going to use? The p28 doesn't have knock. Some of the p30s do and the p72 do.
You can also chip and disable the knock system. I can chip if that helps at all.
Also I don't know if you are going obd0 or obd1 but all the obdos didn't come with knock. The only 2 ecus for vtec are pw0 or pr3. But a pm6,pr4,ps9 can all me modified to run a vtec motor threw turbo edit.