Hello,

I have recently developed a smart card payphone and have used AT89c52. But due to shortage of code memory (8k in 80c52), I had decided to use AT89C55.
What I got is AT89C55WD, but could not program it on ALL-03, ALL-11 and ADVIN PILOT U-40 programmers. I have consulted the data sheet, but could not find any suffix like WD.

Can anybody help me? I have tried 12 chips from 3 different sources, but even a single could not be programmed.