It may be that I have not been clear or perhaps I do not understand your comment. There are two devices, one address $70, one $7C (ones digit and tens digit) on the same bus. I have several of the modules and have tried several different addresses... always the first executes (and displays) perfectly; the other never. Do you suggest that there is some parameter missing from the I2CWRITE statement?

I tried adding ,[$00] in the case another tick was required to complete the "ACK", but no... error. In fact, everything I tried there failed. I thought I understood the syntax, but now I doubt.