Using FreeRTOS build the following system:

The system should consist of three tasks.

• Keypad Task
  • When a key has been pressed this task should scan the keypad to find out what key has been pressed.
  • Initially do NOT use interrupts - this task should just loop and scan the keypad each time.
  • It should then pass on the ascii code of the key pressed to the Key Display Task.
• Key Display Task
  • When keys are pressed on the keypad this task should display them on the LCD.
  • Once the screen is full this task should clear the screen and continue displaying the next pressed keys from position 0 again.
  • This process should happen continuously.

• Temperature task
  • Using the provided ADC library this task should display the temperature on the LCD if it changes by more than 1 degree C.
  • The LCD should be cleared before displaying the Temperature.
  • The Temperature should remain on the screen for 2 seconds.
  • The temperature sensor (lm35) should be polled every second.

Other Requirements:

• The system should only react to a key press and not a release.
• After displaying the temperature the LCD should go back to the key press display it had before as if nothing had happened.
• If a key was pressed while the temperature was being displayed this should be captured and be on the display when the temperature finishes displaying.

HINT:

• Investigate the use of an RTOS queue to send the key ascii code from the Keypad Task to the Key Display Task.
• Protect access to the LCD....