works perfectly with 89C51/52 i didn't use it with 55 but i think it works tooI made one similar to asim khan's but i used a CD4051 analog switch to change between 5 and 12 volts and it works gr8
Re: has anyone made asim khan's programmer ( 89c51 , s51 ,.
I made the asim khan download cable and it worked properly. I used the 74HC245 and remove some unwanted resistors.
However, the speed of downloading is very slow, I think.