May I know where should I put the 0.1uF decoupling caps?Add 0.1uF decoupling caps to the uP
Can't read the schematic, it's too small. What is the circuit supposed to be doing?
the channel 1 is I attach to the first LED.Which pin is channel 1 attached to? Which microcontroller are you using?
May I know what is the pull up resistor ? What is the function of the pull up resistor? How is the pull up resistor going to connect to the output?What is the Vcc? Whatever is is, the 2 volt output with no pullup resistor may be reasonable if it's a micro with "weak" internal pullups.
The power supply is 4.44V, the output pin from PORTD is 3.97V . however when measure LED is 1.9-2.0V . the LED have light up.What do you measure for the Vss supply of the PIC, and what do you measure at the output pins? Do the LEDs light up?