8085-Data Transfer instructions 8085 Microprocessor by Ravinder Nath Rajotiya - September 1, 2020May 10, 20210 Data Transfer Instructions: These instructions are used for transferring data items from one source location to another location called destination. The source can be an immediate number, content of a register or memory or even an input from the peripheral and destination can be a register, memory or any peripheral. The different instructions under data transfer category are listed in table below: 1 MVI Reg/Mem,8-bit data Move immediate 8-bit data in reg/memory 2 MOV Rd, Rs Move content of source register to a destination register 3 MOV Rd, M Move content of memory to a destination register 4 LXI Rp,16-bit Data Move 16-bit immediate data to register pair (BC, DE, HL) 5 LDA 16-bit Address Load Accumulator from memory whose 16-bit address is given 6 STA 16-bit Address Store Accumulator from memory whose 16-bit address is given 7 LHLD 16-bit Address Load HL
8085 Classification of Instructions 8085 Microprocessor by Ravinder Nath Rajotiya - September 1, 2020May 10, 20210 This post describes the different classification of the 8085 instructions. Three possible classifications are made based on size, based on addressing mode supported and the functions performed by them. Examples of each type has also been indicated
8085 Addressing Modes 8085 Microprocessor by Ravinder Nath Rajotiya - August 31, 2020August 31, 20200 Addressing Modes of 8085: The operand or the data item may reside in internal registers, RAM, may come from input device or can be assigned as immediate as part of an instruction. For accessing an operand there is a well-defined way or method. Therefore, we can define addressing modes as the methods of accessing the data byte(operands). 8085 has the following addressing modes : a. Immediate Addressing Mode b. Implicit or Implied Addressing Mode c. Direct Register Addressing Mode d. Direct Memory Addressing Mode e. Indirect memory addressing mode These modes are explained in the following paragraph Immediate addressing mode In this addressing mode the data byte is defined as part of the instruction. 8085 microprocessor supports an immediate to register or immediate to memory assignment, and use
Interrupt Structure of 8085 Microprocessor 8085 Microprocessor by Ravinder Nath Rajotiya - August 28, 2020February 28, 20220 Interrupt structure of 8085 microprocessor: 8085 IC has six pins from PIN 6 to PIN 11, reserved for interrupts these are : TRAP, RST 7.5, RST 6.5, RST 5.5 and INTR. PIN 11 is the interrupt acknowledgement (INTA’) that is generated by the 8085 processor in response to the different interrupts that arrive at the interrupt pin. Figure shows the interrupt structure of 8085 microprocessor. Interrupt priority is shown by the decimal numbers on the extreme left of the figure. As can be see that TRAP has the higher priority marked by digit 1 and INTR has the least priority marked by digit 5 on the left of figure. IVT (Interrupt vector table): IVT contains the interrupt service routine addresses Table-1 (IVT interrupt[t vector
Interrupts in 8085 and interrupt cycle 8085 Microprocessor by Ravinder Nath Rajotiya - August 28, 2020February 28, 20220 We can define interrupt as a process or techniques using which an external slow speed device seek the attention of the microprocessor to informs that it is ready for communication with it. In this post we learn about the interrupt, interrupt cycle and the types of interrupts for 8085 microprocessor