Hello Anton,

i'am using the DS80C320 now for 5 years without any problem. Your problem is maybe the accestime of the ROM/RAM.

It depends on the clockspeed of the crystal for the ds80c320. With the memory cycle stretch option you can stretch the movx-timing.

An applicationnote from Dalles Semi. explains the correlation between the crystal speed and the Latchtype (F/HC/HCT/AC ....) .....

Please check the status of the /EA-PIN. The USER'S GUIDE says:
"connect to ground for compatibility with other 8051 family parts and future versions."

Bye, Dieter.