Hi,
I have built and used Sunrom programmer 1001-3456-v2 (ProLoad Ver. 5.4) for the last 6 months for AT89C52/AT89S52, and am satisfied with it.

Now I want to program AT89C55WD. This always gives an error on Verify Fail at Address 1.

When I put this IC into another USB programmer(UNIPro), it shows blank.

The same AT89C55WD gets programmed in USB programmer(UNIPro).

Whereas the Sunrom programmer is working fine with AT89C52.

Once this Sunrom Programmer worked on 2 of AT89C55WD, but after some time, it started giving the same problem, with the very same ICs. But the ICs are OK when checked in UNIPro programmer.

Is a new version of hardware/firmware/software needed?

I am using 18Vdc power supply. I have also tried by using 15VAC Adaptor, but still I am getting the same problem.

I have also posted it on:
http://www.edaboard.com/ftopic378013.html