8085 Pin Configuration
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The document discusses the pin configuration of the 8085 microprocessor. It begins by providing a basic pin diagram of the 8085 and stating it can address 64KB of memory and operate at up to 3MHz. It then classifies the 40 pins into 7 groups: 1) Address and Data Bus, 2) Control and Status Signals, 3) Power Supply and Clock Frequency, 4) Interrupts, 5) Reset Signals, 6) External/Peripheral Signals, 7) Serial I/O ports. Each group is then described in 1-2 sentences. The document concludes with a thank you.
8085 Pin Configuration
- 1. DAWOOD UNIVERSITY OF ENGINEERING AND TELECHNOLOGY DEPARTMENT OF TELECOMMUNICATION ENGINEERING Microprocessor and Microcontroller System ONLINE MID EXAMINATION-2020 MICROPROCESSOR 8085 PIN CONFIGURATION Presented by: Mr. Noor Nabi Khan Roll No:D-19-TE-28 Date:02-09-2020
- 2. 8085-Pin Diagram First of all we will have a look at the basic Pin diagram of a 8085: This diagram basically describe the architecture of an 8-bit general purpose microprocessor that can address 64Kb of memory. The 8085 has 40 pins and uses the input voltage of 5V for power. This processor can run or perform at the maximum frequency of 3 MHz.
- 3. CLASSIFICATION OF 8085 PINS The pins of the microprocessor are classified into mainly seven groups according to the properties of each pin, studying each pin will be complicated so these pins are grouped to gather which is easier to understand; 1. Address Bus and Data Bus 2. Control and Status Signals 3. Power Supply and Clock Frequency 4. Interrupts 5. Reset Signals 6. External/Peripheral Signals 7. Serial I/O ports
- 4. 1.Address and Bus Data: • The group consists of 16 pins which are named from A0 to A15. • The Address bus from A8 to A15 are unidirectional which means that the bits can flow only in one direction from 8085 to other peripheral devices. It carries most significant 8-bits of memory address • While the Data bus from A0 to A7 are bidirectional which means they can perform in two directions at a time bit can flow in 2 ways. It carries least significant 8-bit address and data bus.
- 5. 2.Control and Status Signals: The control and status signals have three pins each total of 6 pins. Basically these pins or signals are used to check the type of the operations that what operation is going on. Control Signals: RD,WR and ALE. • ALE: It stands for Address Latch Enable. It tells us the address if the pulse is high i.e. 1 and it tells the data when it is low i.e. 0. • WR: It is signal of control Write operation. Data bus is written when the pulse goes low. • RD: It is signal of control Read operation. The selected memory will be read when the pulse is low.
- 6. 3.Power Supply and Clock Frequency: Power Supply pins are those which are used to give power input to the processor through different specific ports: • VCC: It is +5V power supply • VSS: It is the ground reference. • Clock Signals pins: • X1 and X2: the crystals are connected to these two pins. The internal frequency is divided by two. It is basically used for the clock signal generator. • CLK (OUT): This signal can be used as the system clock for other peripheral devices.
- 7. 4.Interrupts: These are request signals. 8085 has five interrupts signals that are used to interrupt the execution of program of command; RST 7.5, RST 6.5, RST 5.5, TRAP and INTR. The microprocessor 8085 accepts the requested interrupt by INTA signal. • INTR: this is an interrupt request signal from devices. • INTA: this is an acknowledgment sent by 8085 after INTR is received.
- 8. 5.Reset Signals: RESET IN: when the signal on this pin is low ‘0’ then the counter set the program to zero. Then the microprocessor is reset. RESER OUT: after the microprocessor is reset this signal indicates that the unit is reset, and then the other devices can also be reset now. 6.External or Peripheral Initiated Signals: In addition to the interrupts and reset signals the 8085 has three external/peripheral initiated signals. • HOLD: the HOLD tell us that the other external device is requesting to use the address and data bus. • HLDA: this is basically a acknowledgment that the HOLD request has been received and the access will be granted in next clock cycle. This goes low(0) after removal of request. • READY: the READY signal tell us that the device can be used fro transfer data. The system has to wait until the READY goes high(1).
- 9. 7.Serial I/O Ports: The serial transmission lines in 8085 are performed by two signals and these signals can be used for communication. • SID: SID is Serial Input Data line. The input data line used for serial input. The data in this input data line is loaded into accumulator when instruction is executed. • SOD: this is Serial Output Data line. This line is used for serial output and the output is set or reset as specified by the instruction.
- 10. CONCLUSION
- 11. THANK YOU