Summary of Disk Based Data Logger using PIC18F458 with Proteus Simulation
This project implements a disk-based data logger using a PIC18F458 microcontroller to sample ADC data and store it sector-by-sector on an ATA/IDE hard disk, controlled via an RS232 serial terminal and fully testable in Proteus VSM. It features interrupt-driven sampling, LBA sector writes/reads, assembly firmware modules for ATA driving, logging, and dump utilities, and is suitable for learning low-level disk interfacing and embedded data acquisition.
Parts used in the Disk Based Data Logger:
- PIC18F458 Microcontroller
- ATA/IDE Hard Disk Drive
- RS232 Serial Interface (Virtual Terminal)
- Resistors (pull-ups and LED current limiting)
- Status LED
- Reset Button
Introduction
How the Project Works (Overview)
The PIC18F458 acts as the main controller, managing data acquisition, buffering, and storage. Data samples are collected using the ADC module, temporarily stored in RAM, and written to an ATA hard disk using standard IDE commands.
User interaction happens through an RS232 serial interface, allowing commands such as starting logging, stopping logging, and dumping stored data. Interrupts ensure accurate timing and efficient background logging while the main loop handles user commands.
Block Diagram / Workflow Explanation
RS232 Interface
The user sends commands via a serial terminal (help, start logging, dump data).Timer & ADC Triggering
Timer0 periodically triggers ADC conversions using interrupts.Data Buffering
ADC samples are stored in a RAM buffer until a full sector is ready.ATA Hard Disk Interface
Buffered data is written to the hard disk using LBA addressing.Data Retrieval
Stored sectors can be read back and displayed as hexadecimal values over RS232.
Key Features
Direct ATA/IDE hard disk interfacing without external controllers
Interrupt-driven ADC sampling for consistent data logging
Sector-based data storage using LBA addressing
RS232 command-line interface via virtual terminal
Complete Proteus VSM simulation support
Written entirely in PIC18 assembly language
Components Used
PIC18F458 Microcontroller
ATA/IDE Hard Disk Drive
RS232 Serial Interface (Virtual Terminal)
Resistors (pull-ups and LED current limiting)
Status LED
Reset Button
Applications
Embedded data logging systems
Sensor data recording and monitoring
Industrial data acquisition prototypes
Learning ATA/IDE protocol fundamentals
Advanced PIC microcontroller training projects
Explanation of Code (High-Level)
The firmware is structured into clear functional modules:
Initialization Routines
Configure USART, ADC, timers, I/O ports, and reset logging pointers.Command Handler
Processes user input commands such as help, version, log, and dump.Interrupt Handlers
High priority: Timer0 overflow triggering ADC conversions
Low priority: ADC completion and buffer management
ATA Driver Routines
Handle register reads/writes, sector read/write operations, and LBA addressing.Logging Engine
Buffers ADC data and writes it to disk when a sector is full.Dump Utility
Reads logged sectors from disk and outputs data via serial in hex format.
Source Code
; General temps
TMP1 equ 0x000000
TMP2 equ 0x000001
; Current LBA sector address for reading/wring
ATA_A0 equ 0x000002
ATA_A1 equ 0x000003
ATA_A2 equ 0x000004
ATA_A3 equ 0x000005
; Counter used to track data words read/written to/from ATA
ATA_CNT equ 0x000006
; High priority interrupt temps
STATUS_TEMP_H equ 0x000007
WREG_TEMP_H equ 0x000008
BSR_TEMP_H equ 0x000009Proteus Simulation
In Proteus, the simulation accurately models the PIC18F458, ATA hard disk interface, and RS232 communication.
When the simulation runs:
A virtual terminal displays command prompts
Logging starts and stops via keyboard input
Disk sectors are written and read in real time
Data appears as hexadecimal output during dump operations
This makes it ideal for testing firmware logic without physical hardware.
(FAQs)
Conclusion
This Disk Based Data Logger using PIC18F458 is a powerful learning project that blends embedded systems, disk protocols, and real-time data acquisition. It offers hands-on insight into how microcontrollers interact with mass storage devices at a low level.
Perfect for advanced learners, this project builds strong fundamentals in firmware design, Proteus simulation, and hardware interfacing—all essential skills for modern embedded engineers.
- Can this project run entirely in Proteus simulation?
Yes, it is fully designed for Proteus VSM and works without physical hardware. - Why is an ATA hard disk used instead of EEPROM or SD card?
It demonstrates low-level disk control and sector-based data storage. - Can the logging interval be changed?
Yes, by modifying Timer0 settings and ADC trigger timing in firmware. - Is this compatible with other PIC18 microcontrollers?
Only devices with similar I/O and memory mapping would be suitable. - Why is assembly language used instead of C?
Assembly provides precise timing and full control over ATA signaling. - Can sensors be added to this project?
Yes, any analog sensor can be connected to the ADC input. - What baud rate does the serial interface use?
The firmware configures RS232 communication at 9600 baud. - How is data stored on the disk?
Data is written sequentially using Logical Block Addressing (LBA).
