Introduction to Microcontrollers Lab Manual - Microchip

LABS
10.2.2.4 FUNCTIONAL DESCRIPTION
The system will power up and assume that it is on level 1. The service request indicators
on each level will be turned off. The state will default to Idle Request.
The elevator cart controller has four states: Idle Request, Moving Request, Idle Target,
and Moving Target. The Request states are a result of the service request buttons, and
the Target states are a result of the target being entered from the terminal emulator over
the UART.
When a request button is pressed, the service request indicator will be turned on. When
in Idle state, a request from any level (except the current level) will cause the state to
change to the Moving Target state. The elevator will move in the correct direction given
its current location and the location of the service request. The elevator will move to the
level of the requested level, turn off the service requested indicator, and then move to
the Idle Target state. Subsequent button presses on service request buttons will be
ignored until the current service is completed.
When in Idle Target state, the system is waiting for the user to enter the desired target
level. When a valid number is entered, the system will then move to the desired level.
When this movement is completed, the system will return to Idle Request, at which time
subsequent service requests will be processed.
At all times the level display on the terminal emulator will indicate the current level (if in
Idle Request or Idle Target state), or the level that is being approached during movement.
10.2.2.5 POSSIBLE ENHANCEMENTS TO FUNCTIONALITY
There are many ways this system could be made better. Consider adding these functional
enhancements:
• Queueing of service requests
• Simulating ramping up and down speed of the elevator cart
• Blinking level indicator when that level is the target level and the cart is
approaching
• ...
DS51963A-page 70 2011 Microchip Technology Inc.