TIMING DIAGRAM in mechatronicssunject-1.pptx

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1. What is Timing Diagram The timing diagram of the 8085 microprocessor shows the relationship between various signals (such as clock, address, data, and control signals) and the phases of execution of an instruction. It helps us understand how the microprocessor fetches, decodes, and executes instructions. A T-state (or clock cycle) is the basic time unit of operation in the 8085 microprocessor. It is defined by the duration of one clock pulse, which is the smallest unit of time the microprocessor uses to complete its internal operations. Each instruction in the 8085 microprocessor is broken down into machine cycles, and each machine cycle is further divided into T-states . The 8085 operates based on a clock, and during each T-state, certain internal tasks (like fetching data, decoding, reading/writing) are performed.

2. Main Phases of the Timing Diagram Opcode Fetch Cycle Memory Read Cycle Memory Write Cycle I/O Read Cycle I/O Write Cycle

3. SHLD - Store HL Direct It is a instruction in the 8085 microprocessor is used to store the contents of the HL register pair into two consecutive memory locations specified by a 16-bit address. Here’s a breakdown of how it works, including an example of timing involved. SHLD – TIMING DIAGRAM Instruction Overview: Mnemonic: SHLD a16 Operation: Stores the contents of the HL register pair into the memory locations starting from the address a16. Size: 3 Bytes (1 Byte for the opcode and 2 Bytes for the address). Addressing Mode: Direct addressing. Opcode: 22 (in hexadecimal). Instruction Overview:

4. Example: Instruction: SHLD 4050H Initial Register Contents: H register: BBH L register: AAH I nitial Memory Contents: Memory at 4050H: CCH Memory at 4051H: DDH After Execution of SHLD 4050H: Memory at 4050H: AAH (content of L register) Memory at 4051H: BBH (content of H register)

5. EXECUTION STEPS: Opcode Fetch Cycle Read address Read address Write to memory Write to memory