I used a vp290 programmer kit to programm 89v51rd2fa (44pin ic), and was unable to load program(64kb)in it.and i loaded lower memory program(30kb) it worked.
But i loaded the same program(64kb) to 89v51rd2bn using the same kit this was also worked and i dont understand what is the problem with 89v51rd2fa.
Need your suggestions...