i have same problem in last reply

problem form circuit work with 89c55 but not work with 89c55wd
i cheak 30 pcs of 89c55wd with parameter to parameter :


1.Reset problem : the 89c55wd is require powerfull low state after reset this is not problem for circuit use 10uf+10k but for example if you use max645 (supervisor) you have require pwerfull pulldown resistor (2.2k !) the reset pin require 6ma to sink
for normal wotk

2. programming : i have good programmer and it can program 89c55wd but i see more faied
in programming

3. fan out : 89c55wd very sensetive to overload and very fast failed !

i use 80ma 5v high pulse to 89c55 and 59c55wd
all wd faild (5pcs) but any normal 89c55 not failed !!!!!

i move of 89c55wd i think it bad product of atmel !