Features Of Intel 8085 Are As Follows:
1. It Is An 8-Bit Microprocessor I.E. It Can Accept, Process, Or Provide 8-Bit Data Simultaneously.
2. It operates on a single +5V power supply connected at Vcc; the power supply ground is connected to Vss.
3. It operates on a clock cycle with a 50% duty cycle.
4. It has an on-chip clock generator. This internal clock generator requires a tuned circuit like LC, RC, or crystal. The internal clock generator divides the oscillator frequency by 2 and generates a clock signal, which can be used for synchronizing external devices.
5. It can operate with a 3 MHz clock frequency. The 8085A-2 version can operate at a maximum frequency of 5 MHz.
6. It has 16 address lines, hence it can access (216) 64 Kbytes of memory.
7. It provides 8-bit I/O addresses to access (28 ) 256 I/O ports.
8. In 8085, the lower 8-bit address bus (A0 – A7) and data bus (D0 – D7) is Multiplexed to reduce the number of external pins. But due to this, external hardware (latch) is required to separate address lines and data lines.
9. It supports 74 instructions with the following addressing modes :
- Immediate
- Register
- Direct
- Indirect
- Implied
10. The Arithmetic Logic Unit (ALU) of 8085 performs :
- 8- bit binary addition with or without carry
- 16- bit binary addition
- 2-digit BCD addition.
- 8-bit binary subtraction with or without borrow
- 8-bit logical AND, OR, EX-OR, complement (NOT), and bit shift operations
11. It has an 8-bit accumulator, flag register, instruction register, six 8-bit general purpose registers (B, C, D, E, H, and L), and two 16-bit registers. (SP and PC). Getting the operand from the general purpose registers is faster than from memory. Hence skilled programmers always prefer general-purpose registers to store program variables than memory.
12. It provides five hardware interrupts TRAP, RST 7.5, RST 6.5, RST 5.5, and INTR.
13. It has serial I/O control which allows serial communication.
14. It provides control signals (IO/M, RD, WR) to control the bus cycles, and hence external bus controller is not required.
15. The external hardware (another microprocessor or equivalent master) can detect which machine cycle microprocessor is executing using status signals (IO/M, S0, S1). This Feature of the 8085 Microprocessor is very useful when more than one processor are using common system resources (memory and I/O devices).
16. It has a mechanism by which it is possible to increase its interrupt handling capacity.
17. The 8085 has the ability to share the system bus with a Direct Memory Access controller. This Feature of the 8085 Microprocessor allows transferring of large amounts of data from an I/O device to memory or from memory to an I/O device with high speeds.
18 . Features of 8085 Microprocessor can be used to implement three-chip microcomputers with supporting I/O devices like IC 8155 and IC 8355.
19. It has a mechanism by which it is possible to increase its interrupt handling capacity.
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