Embedded Systems - PICF877A Development Board.

Project Overview and Inspiration.

For my module for Embedded Systems at the University, we were tasked with creating a GreenHouse Control System using a PIC QL200 Development Board.

System Overview/Features.

The System contains a time of day clock and have features such as:

  • Setting up date/time.
  • Display of current temperature.
  • Display current date/time/month.
  • Entry of trigger temperaures.
  • Two output controls; one for a heating circuit and one for air circulation.
When the temperature drops below a set threshold, the heating output turns on. If the temperature continues to decrease, an alarm signal is activated. The user can clear the alarm signal by pressing the assigned clear button on the Development board. When the temperature rises below a set threshold, a cooling output turns on. If the warmth continues to rise, an alarm signal is activated. The user can reset the alarm by pressing the designated button on the development board.

Date/Time Setup and Display.

Setting up of the date/time display was managed and programmed using the lcd12864 LCD panel and the lcd12864 datasheet. Setting up commands such as cursor placement, clear screen, circuitry setup, and read/write timings are managed while strictly following the datasheet.

Current Temperature Management.

Temperature sensing hardware was the DS18B20 Programmable Resolution 1-Wire Digital Thermometer by Dallas Semiconductor. Temperature/Data Relationships were managed using the associated Datasheet showing Temperature(in Celcius) conversion to Binary output(Digital Output) and Hexadecimal equivalent. Initialization and ROM search was accomplished by strictly following the DS18B20 Thermometer Datasheet.

Timekeeping Chip.

Date/Time management was managed by the DS1302 Trickle Charge Timekeeping chip which enabled:

  • Real-time clock counts seconds, minutes, hours.
  • Date of month, day of month/week and month.
  • Leap year compenstation up to the year 2100.
Data input and output operations were programmed following the PIC's SCLK cycles and following the hardware Datasheet.

Resources/Tools Used.

  • PICF877A Development Board.
  • DS18B20 Programmable Resolution 1-Wire Digital Thermometer by Dallas Semiconductor.
  • lcd12864 LCD panel.
  • DS18B20 datasheet.
  • lcd12864 LCD datasheet.
  • MP LABS IDE.
  • C language
  • Assembly Language.

Project Source Code Link.

https://github.com/Kikumu/A-GreenHouse-climate-control-system-with-a-PICF877A

Overall System Logic Flow.

Menu.

Set Time.

Set Date.

Set Threshold.