Hi,paul my name is Terry.chen

I have visit u web , and I am interst for ur development for 8051 board.

so i try to design ur min board for 8051 which only ram .

but some question is make.

Sometimes ,I have try the board successful but sometime fail.

now I want to ask why if the result fail the board always get "null" from max'232

i have check all the pin is connect and gnd connect with rs232,very sure.

but the fail I always get "null" if i start for DC power.

if i didn't connect DC power rs232 can work.

but if i connect DC power it always recevied "null" continues