8085 Microprocessors Notes

8085 MPU is an 8-bit microprocessor using NMOS technology in 40 pin dual in- line (DIP) package. Pin Diagram of 8085 Microprocessor Power supply and frequency signals: Vcc : Single +5V power supply. Vss : Ground reference. X1 and X2: A crystal oscillator is connected to these pins. Data bus and address bus: AD0 - AD7: 8-bit data bus (D0 - D7) is multiplexed with the lower half of 16-bit address bus (A0 - A7). A8 - A15: The upper half of 16-bit address bus appears on these pins. Control and status signals: ALE:  ALE stands for Address Latch Enable. The lower half of address bus (A0 - A7) is available only during T1 of machine cycle. This is also necessary during T2 and T3 of machine cycle. Therefore the lower half of address bus must be latched to T1 of machine cycle so that it is available throughout the machine cycle. This important function is done through ALE signal. Read and Write signals: These two signals are active low signal...