I was using AD7734 in 0 to +5v mode with CLAMP = 1. It was working nicely.
However, I changed the configuration to CLAMP = 0 and I get only 0000s when I send negative voltages. The sign bit behaves correctly, but the negative results are clamped. If I go above 5V, the results are not clamped. So the clamp bit is set correctly, but does not work for negative voltages?