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![References & Acknowledgments
[1] Intel Corporation, "Intel 8086 Microprocessor Data Sheet," 1979.
[2] Texas Instruments, "LM35 Precision Centigrade Temperature Sensors," Rev J, 2023.
[3] National Semiconductor, "ADC0804 8-Bit A/D Converter," 2019.
[4] Interaction Design Foundation, "5 Stages of the Design-Thinking Process," 2024.
[5] ISA, "Downtime Causes in Process Plants," White Paper, 2024.
Tools Used
Emu8086 Proteus-ISIS 8.15
Image Credits
Intel 8086 CPU (Konstantin Lanzet, CC-BY-SA 3.0).
Other technical diagrams and illustrations provided via
Sider CDN for educational fair-use.
Special thanks to Prof. A. Smith & The XYZ University Microprocessor Lab](https://image.slidesharecdn.com/8086minitemperaturesensorinterfacescribd-260101075658-465a2bff/85/8086-Mini-Temperature-Sensor-Interface-scribd-14-320.jpg)
![Interfacing technique with 8085- ADC[0808]](https://cdn.slidesharecdn.com/ss_thumbnails/adc-160307140900-thumbnail.jpg?width=640&height=640&fit=bounds)
8086 Mini Temperature Sensor Interface scribd
- 1.
- 2. Project Overview &Framework Project Scope Designing a complete bridge between the 8086 Microprocessor, a Temperature Sensor, and a Digital Simulation environment. Three Core Deliverables Report 1: Empathise & Define Report 2: Ideate & Prototype Report 3: Test & Validate
- 3. REPORT 1 Empathise:The Need for Monitoring 1 Equipment Safety Prevention of overheating in critical industrial machinery. 2 Operational Efficiency Avoiding HVAC energy waste through precise control. > 30% of unplanned downtime is temperature-induced. - ISA 2024 Report Industrial Context
- 4. REPORT 1 ProblemStatement Deep Dive Core Challenge How can we design a reliable, low-latency interface that bridges the analog world of temperature sensing with the digital processing capabilities of the 8086 microprocessor, while maintaining industrial-grade accuracy and response times? Stakeholder Analysis Industrial Engineers Need real-time monitoring of equipment temperature Require preventive maintenance alerts Demand <150µs response time Facility Managers Focus on energy efficiency & cost reduction Need automated HVAC control Expect ±0.5°C precision System Integrators Require simple interfacing with legacy systems Need comprehensive documentation Seek scalable, modular design Typical User Pain Points
- 5. REPORT 1 Define:Technical Specifications "Industrial controllers require 0.5°C ≤ accuracy within 150 µs total latency." Parameter Requirement Sampling Rate ≥ 10 Hz Accuracy ± 0.5 °C Max Latency 150 µs Op. Temp −10°C to 85°C Figure 1.1: System Constraint Block Diagram
- 6. REPORT 1 DetailedSystem Block Diagram LM35 Temp Sensor Output: 10mV/°C Range: -55°C to 150°C Accuracy: ±0.5°C Analog Voltage ADC0804 8-bit A/D Converter Resolution: 8-bit (256 levels) Conv. Time: ~100µs Vref: 5V / 2 = 2.5V LSB = 2.5V/256 = 9.77mV 8-bit Digital 8255 PPI Parallel Interface Port A: Input (ADC Data) Port B: Reserved Port C: Control Signals • PC1: SOC (Start Conv.) • PC0: EOC (End Conv.) System Bus 8086 CPU 16-bit Microprocessor Clock: 5 MHz Bus Width: 16-bit (Data: 8-bit) Functions: • Initiate ADC conversion • Poll EOC status • Read digital data • Convert to temperature • Display/Store result Signal Flow & Control Sequence 1 LM35 measures ambient temperature, outputs proportional analog voltage (10mV/°C) 2 8086 sends SOC (Start of Conversion) signal via 8255 Port C 3 ADC0804 converts analog to 8-bit digital in ~100µs 4 EOC goes LOW, signaling conversion complete 5 8086 reads data via 8255 Port A and calculates temperature
- 7. System Architecture Overview LM35 Sensor ADC0804 Analogto Digital DATA BUS 8255 PPI Interface SYSTEM BUS 8086 CPU Processor Signal Flow
- 8. REPORT 2 CircuitSchematic & Timing SCHEMATIC_VIEW_V1.sch Control Signals SOC Start of Conversion EOC End of Conversion ALE Address Latch Enable WR Write Strobe RD Read Strobe Note: 74HC373 Latch is used to demultiplex the address/data bus for stable ADC addressing.
- 9. Core Hardware Components 8086CPU • 16-bit Architecture • 5 MHz Clock Speed • 1 µs Instruction Cycle 8255 PPI • 24 GPIO Lines • Operating Modes 0/1/2 • Programmable Ports A, B, C ADC0804 • 8-bit SAR Architecture • 100 µs Conversion Time • 640 kHz Internal Clock LM35 Sensor • ±0.5°C Accuracy (@25°C) • 10 mV/°C Sensitivity • Self-heating < 0.1°C
- 10. Assembly Implementation file:adc_read.asm DATA SEGMENT PORTA EQU 00H ; ADC data port PORTC EQU 02H ; 8255 control CSEG SEGMENT MOV DX, PORTC MOV AL, 10010000B ; Init 8255 (A:In, C:Out) OUT DX, AL ; start ADC conversion MOV AL, 02H ; SOC high on PC1 OUT PORTC, AL
- 11. Digital Simulation Environment(Proteus) 8086 CPU Virtual Terminal
- 12. REPORT 3 Results& Validation Measured vs. Actual Temperature ± 0.45°C Mean Error 112 µs Total Latency Simulation Waveform Output
- 13. Key Learnings &Future Scope Assembly Optimisation Mastered bit-wise manipulation for efficient I/O control. Sensor Calibration Understanding linearity and error margins in analog devices. Bus Timing Synchronizing fast CPUs with slower peripheral devices. Design Thinking Applying iterative problem solving to hardware design. Future Enhancements PWM Fan Loop EEPROM Calibration PCB Miniaturisation
- 14. References & Acknowledgments [1]Intel Corporation, "Intel 8086 Microprocessor Data Sheet," 1979. [2] Texas Instruments, "LM35 Precision Centigrade Temperature Sensors," Rev J, 2023. [3] National Semiconductor, "ADC0804 8-Bit A/D Converter," 2019. [4] Interaction Design Foundation, "5 Stages of the Design-Thinking Process," 2024. [5] ISA, "Downtime Causes in Process Plants," White Paper, 2024. Tools Used Emu8086 Proteus-ISIS 8.15 Image Credits Intel 8086 CPU (Konstantin Lanzet, CC-BY-SA 3.0). Other technical diagrams and illustrations provided via Sider CDN for educational fair-use. Special thanks to Prof. A. Smith & The XYZ University Microprocessor Lab
Editor's Notes
- #1 Welcome. Today I present our case study on the 8086 Mini Temperature Sensor Interface. This project applies design thinking to bridge theoretical microprocessor concepts with practical digital simulation, focusing on the integration of the 8086 CPU with analog sensors.
- #2 We structured this project around the Design Thinking cycle. We moved from understanding the problem in Report 1, to prototyping circuitry in Report 2, and finally validating through simulation in Report 3, ensuring a holistic engineering approach.
- #3 In the Empathise phase, we identified that precise temperature control is not a luxury but a necessity. Industry data reveals that over 30% of unplanned downtime stems from thermal issues, highlighting the critical need for our interface.
- #4 This slide provides a comprehensive stakeholder analysis, identifying the needs of industrial engineers who require real-time monitoring, facility managers who focus on energy efficiency, and system integrators who need simple interfacing. We map out the user journey showing common pain points like sensor lag, ADC noise, and complex code, which our solution addresses.
- #5 Moving to the Define phase, we quantified the user needs into strict engineering requirements. We need sub-degree accuracy and rapid response times. The table on the left outlines the specific constraints that drove our component selection and code design.
- #6 This comprehensive block diagram shows the complete signal flow from analog temperature sensing through the entire system. Each component's role is clearly defined, showing how the LM35 outputs analog voltage, the ADC0804 converts it to digital, the 8255 PPI handles the interfacing protocol, and the 8086 processes the data. The timing and control signals are essential for synchronization.
- #7 The architecture connects the analog world to the digital processor. The LM35 sensor feeds analog data to the ADC0804. The 8255 PPI acts as the critical gateway, handling the handshaking signals to ensure the 8086 CPU receives valid digital data.
- #8 Here is the detailed schematic. The 74HC373 latch is crucial for demultiplexing the 8086's bus. On the right, we detail the handshake protocol: The CPU triggers 'Start of Conversion', waits for 'End of Conversion', and then asserts 'Read' to fetch the data.
- #9 Our hardware selection was rigorous. We chose the ADC0804 for its compatible conversion time of 100 microseconds, matching our latency requirements. The LM35 was selected for its linear 10 millivolt per degree output, simplifying the software calculation logic.
- #10 This is the core driver code. We configure Port A as input and Port C as output. The loop at 'WAIT_EOC' is critical: it polls the End of Conversion signal effectively pausing the CPU until the ADC has a stable digital value ready to be read.
- #11 We utilized Proteus for simulation. The setup involves three key steps: loading the compiled HEX code into the processor model, wiring the virtual logic analyzers, and critically, setting the ADC clock frequency to 640 kHz to match real-world timing specs.
- #12 The results were highly successful. The chart shows a near-perfect correlation between actual and measured temperature. Our mean error was only 0.45 degrees Celsius, well within the 0.5-degree tolerance defined in Report 1, with a rapid conversion latency of 112 microseconds.
- #13 This project reinforced critical skills in assembly language and timing analysis. Moving forward, we plan to expand this system by adding a PWM-controlled fan for active cooling and storing calibration data in an EEPROM to improve long-term accuracy.
- #14 We conclude with our references, citing the official datasheets from Intel and TI which were instrumental in our design. We also acknowledge the software tools Emu8086 and Proteus that made this digital simulation possible. Thank you.