Dear 8052.com fans, I thank you all for your valuable comments. My solution that I came up with is realy radical. I am going to equip my circuit with an external watchdog and keep using 89C51 and avoid myself from 55WD for my future involvements.

BTW, a couple of weeks ago, I had made an order for 89C420 for a relatively complex project, but I am fairly discouraged now using this family.

Thank you.

Rustu