This paper describes the design of an FPGA-based DS18B20 temperature monitoring and alarm system

utilising the Altera Cyclone IV series EP4CE6E22C8 as the core component. The system logic design

compilation and hardware implementation were carried out using Verilog HDL within the Quartus II development environment. The system operates at a 50 MHz clock frequency and employs a finite state machine to control the DS18B20 for single-bus communication and temperature data reading. After sign determination and base conversion

the raw data is dynamically displayed on a display screen to two decimal places. The system's initial high and low temperature thresholds are set at 30°C and 10°C respectively; users can adjust these via push-button controls

whilst the programme simultaneously enforces constraints on the threshold range and the relationship between the upper and lower limits. When the measured temperature is not lower than 30°C or not higher than 10°C

the buzzer and LED are activated to trigger an audible and visual alarm; the alarm is automatically deactivated once the temperature returns to within the threshold range. Hardware test results indicate that the system is capable of stably performing temperature acquisition

data display

threshold adjustment and out-of-limit alarms

thereby meeting the expected design requirements.