its a 89c55wd mpu

port 0 is an 8 bit open drain bi-directional i/o port, each pin can sink 8 ttl inputs internal pullups are used for access to external program/data memory.

for port 0 external pullups are required for program verification.



i made some changes to the schematic, you can check it out again.

http://www.8052.com/users/ericmcn/mpu.jpg


i added the caps and put in a maxim 6731 reset ic,. not sure if this will work or not.......!