harnam,



instead of writing from MCU you may write from 85 MPU. why this external circuitury is there i cant understand where 8051 itsself has 32 io line, yeah i may not drive relays but ULN2003 makes it possible. 8051 designed to provide processing capability ans i/os, timers , communication all in one 1. two ports are wasted for just 16/ios. no problem 16 i/os for 16 i/os. but why external circuitury?

abhishek