تعريفPort 1 فىAT89S52
Port 1 is an 8-bit bi-directional I/O port with internal pullups.
The Port 1 output buffers can sink/source four TTL inputs.
When 1s are written to Port 1 pins, they are pulled high by
the internal pullups and can be used as inputs. As inputs,
Port 1 pins that are externally being pulled low will source
current (IIL) because of the internal pullups.
لزيادة مداخل الميكرو استعمل IC 74HC151N
المشكله فىprotues
بورت1 دائما عالى PULLUP فعندما يكون خرج (74HC151(LOW المتصل ببورت 1
يعطى علامه صفراء اى شورت سيركت
مساعده من متخصصين 8051
