04. a) Write an So51 C program to send values 00 through FFH to port Pl. b) Write an 8051 C program to send values -3 to +3 to port Pl. ite an S051 C program to togele all bits of Pl (berween 55H and AAH) with some delay. ) A door sensor is connected to Pl.1 and a buzzer to P1.7. Write an 8051 C program to monitor the sensor and when it opens Co) sound the buzzer by sending a square wave of 50% duty cycle using the delay routine of Q1